Re: [j-nsp] load balancing in Route reflector scenario
Hello, I have tried for the last 3 years to push all vendors to implement something like this: http://tools.ietf.org/html/draft-raszuk-bgp-optimal-route-reflection-00 But they never find a Bussiness Case to deploy it. It good be great to have a smart route reflector that sends the best NH to each remote PE, depending of the IGP and metric of the remote PE, so the RR will give NextHop 1 to the router A since it knows the IGP topology and know what router A would choose (assuming IGP as the factor to break the even between NHs) and the same RR will send Next Hop 2 to the router B since (again) knows the best NH for router B since RR knows the IGP topology. To make this smart super RR it is necessary for the RR to calculate Dijstra as if the RR were the remote router and use this calculation to choose the best NH for this remote router. You will have just one or two super RR and more idle routers since they will just have one full-routing table with the best NH. Regards. Ignacio 2011/9/6 Mark Tinka mti...@globaltransit.net On Tuesday, September 06, 2011 09:51:43 PM P.Narayana Swamy wrote: It seems add-path feature comes with hidden cli :) Typically, this would mean it's not a supported feature :-). Cheers, Mark. ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] load balancing in Route reflector scenario
It seems add-path feature comes with hidden cli :)
edit protocols bgp group add]
core1@swamy# show
family inet {
unicast {
add-path {
send {
path-count 6;
}
}
}
}
After enabling add-path, path-id is also advertised for the total # of
next-hops for the same prefix.
Hope this helps
Thanks and regards,
Swamy
Message: 1
Date: Tue, 30 Aug 2011 18:36:35 +0800
From: Mark Tinka mti...@globaltransit.net
To: juniper-nsp@puck.nether.net
Subject: Re: [j-nsp] load balancing in Route reflector scenario
Message-ID: 201108301836.43964.mti...@globaltransit.net
Content-Type: text/plain; charset=us-ascii
On Thursday, August 11, 2011 04:02:13 AM Zaid Hammoudi
wrote:
Keegan,
Look into add-path, something that is not supported in
JUNOS yet, but will be sometime this year.
http://tools.ietf.org/html/draft-walton-bgp-add-paths-06
http://www.nanog.org/meetings/nanog48/presentations/Tuesd
ay/Ward_AddPath_N48.pdf
http://www.juniper.net/us/en/local/pdf/whitepapers/200034
5-en.pdf
Earlier on this year, we really needed this feature but only
realized that it was still under IETF development, and
hadn't even been considered for reasonable development by
the vendors.
We ended up working within the natural constraints of MPLS
and IP to get what we wanted, but think the BGP Add Paths
feature would certainly come in very handy due to some of
the information hiding route reflectors introduce.
Cheers,
Mark.
___
juniper-nsp mailing list juniper-nsp@puck.nether.net
https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] load balancing in Route reflector scenario
On Tuesday, September 06, 2011 09:51:43 PM P.Narayana Swamy wrote: It seems add-path feature comes with hidden cli :) Typically, this would mean it's not a supported feature :-). Cheers, Mark. signature.asc Description: This is a digitally signed message part. ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] load balancing in Route reflector scenario
Looks like add-path is now available Junos 11.3 Cheers, Ben On 30/08/2011, at 8:36 PM, Mark Tinka wrote: On Thursday, August 11, 2011 04:02:13 AM Zaid Hammoudi wrote: Keegan, Look into add-path, something that is not supported in JUNOS yet, but will be sometime this year. http://tools.ietf.org/html/draft-walton-bgp-add-paths-06 http://www.nanog.org/meetings/nanog48/presentations/Tuesd ay/Ward_AddPath_N48.pdf http://www.juniper.net/us/en/local/pdf/whitepapers/200034 5-en.pdf Earlier on this year, we really needed this feature but only realized that it was still under IETF development, and hadn't even been considered for reasonable development by the vendors. We ended up working within the natural constraints of MPLS and IP to get what we wanted, but think the BGP Add Paths feature would certainly come in very handy due to some of the information hiding route reflectors introduce. Cheers, Mark. ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] load balancing in Route reflector scenario
On Tuesday, September 06, 2011 08:18:26 AM Ben Dale wrote: Looks like add-path is now available Junos 11.3 Cool. The reasons to move to 11.x are piling, but we'll remain cautious for now. Thanks, Dale. Cheers, Mark. signature.asc Description: This is a digitally signed message part. ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] load balancing in Route reflector scenario
On Thursday, August 11, 2011 04:02:13 AM Zaid Hammoudi wrote: Keegan, Look into add-path, something that is not supported in JUNOS yet, but will be sometime this year. http://tools.ietf.org/html/draft-walton-bgp-add-paths-06 http://www.nanog.org/meetings/nanog48/presentations/Tuesd ay/Ward_AddPath_N48.pdf http://www.juniper.net/us/en/local/pdf/whitepapers/200034 5-en.pdf Earlier on this year, we really needed this feature but only realized that it was still under IETF development, and hadn't even been considered for reasonable development by the vendors. We ended up working within the natural constraints of MPLS and IP to get what we wanted, but think the BGP Add Paths feature would certainly come in very handy due to some of the information hiding route reflectors introduce. Cheers, Mark. signature.asc Description: This is a digitally signed message part. ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] load balancing in Route reflector scenario
Hi Harry, default, differences in route preference cause a JUNI to prefer an IGP route while ios prefer the bgp routs over IGP. Let's make a clear distinction between preferring eBGP route versus iBGP route. Talking CSCO here eBGP admin distance is as you say 20 while iBGP as even the URL provided by yourself says it is 200. So keeping in mind that usually hot potato routing is a desired behaviour preferring EBGP learned path is highly recommended for a given prefix. If you say that JUNI is to prefer IGP route over BGP one I am sure you must be referring to IBGP and not EBGP, but this is exactly the same in both vendors. W/o this knob replacing a cisco with a juniper can result in previously advertised bgp routes no longer being advertised. I can rest assure you that this was not the main intention of this knob :) Cheers, R. I always thought that advertise-inactive was to make a juniper act like a cisco with regard to BGP route announcements, when, by default, differences in route preference cause a JUNI to prefer an IGP route while ios prefer the bgp routs over IGP. In junos, only the active route is readvertised/subject to export policy. With advertise-inactive you can make a juniper router, whose active route is an IGP route, advertise into BGP the best bgp path, which here is inactive due to the igp route being preferred. W/o this knob replacing a cisco with a juniper can result in previously advertised bgp routes no longer being advertised. From: http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094823.shtml eBGP 20 . . . OSPF 110 From: http://www.juniper.net/techpubs/software/junos/junos64/swconfig64-routing/html/protocols-overview4.html OSPF internal route 10 IS-IS Level 1 internal route 15 . . . BGP 170 HTHS. -Original Message- From: juniper-nsp-boun...@puck.nether.net [mailto:juniper-nsp-boun...@puck.nether.net] On Behalf Of Keegan Holley Sent: Wednesday, August 10, 2011 2:48 PM To: rob...@raszuk.net Cc: juniper-nsp@puck.nether.net Subject: Re: [j-nsp] load balancing in Route reflector scenario 2011/8/10 Robert Raszukrob...@raszuk.net Hi Keegan, I think the advertise inactive knob turns that off, but I don't know for sure because I've never tried it. I know it's not supported on cisco routers. The reason for it is the size of the BGP table. So if the table is 400k routes and you have 5 different ISP's and you advertise every route that would be 2M routes in the table. Since BGP doesn't allow multiple version of the same route in the routing table (separate from the BGP table where incoming routes are stored) you would still only use the original 400K the other 1.8M routes would just go unused unless you manipulated them some how. Advertise inactive is not about what get's advertised - it is about if the best path is advertised or not. And if is decided based on the check if the BGP path to be advertised is inserted in the RIB/FIB or not. Oh I see. I have never used that command so thanks. Most of the above example was what would happen if BGP advertised everything it learned instead of just the best path or the path in the routing table btw. By default Junos and IOS-XR advertise only those best path in BGP which actually are installed into forwarding. Advertising inactive knob will overwrite it. Wouldn't this lead to traffic being blackholed? If all the routes for a given destination are inactive would this still cause BGP to advertise a route for them? IOS classic/XE (for historical reasons) advertises all best paths from BGP table and to enforce it not to advertise what has not been installed into RIB/FIB there is knob called suppress inactive. Cheers, R. ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] load balancing in Route reflector scenario
Hi Keegan, Nope ... there can be other producers of the same route (OSPF, ISIS, STATIC) which will be in the RIB. If not there is always next step - less specific route to be used. I suppose there's a use for this or the feature wouldn't exist, but why would you have a route in the IGP that's not in BGP no no ... this entire discussion is about the case where the identical prefix is in both producers ... for example in OSPF and in eBGP. If it is only in one non of this what we are talking here applies. but still needs to receive traffic from routers running an IGP and BGP but not learning the route from the IGP. It is as said the other way around. Why not just import the route(s) into BGP. It just seems like this command may cause unexpected behavior to add features that can be configured in a more graceful manner. Very simple example: Some destination is reachable over EBGP ... the same route is advertised into AS via IBGP. All good. Now for some reason an operator is ordered to redirect all traffic going to dst X to go via some screening box. So on this said ASBR which normally would just switch out the packets, NOC guy is inserting a static route into RIB to say all which dst ix X go to this box. Then effectively this would cause BGP to stop advertising it as the RIB active route is now from static and not BGP. That's just one of the use case of traffic redirection by control plane/routing twick - yet not impacting the BGP operation. Cheers, R. ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] load balancing in Route reflector scenario
Juniper does not have a specific preference for ebgp vs ibgp. The active route selection process does prefer e over i, so in that regard IOS and JUNI are the same. Where in my message did I say IBGP? I was referring to an EBGP route vs an OSPF/IGP route. In which case the cisco will select the EBGP, and readvertise it downstream, while a JUNI will select the ospf version, and therefore, by default, not readvertise the BGP version. As such placing a juni into that spot results in a different set of bgp route advertisements, which again, stem from different global route preference. I can rest assure you that this was not the main intention of this knob :) Your statement above is incorrect. This is the intended use of the knob. Regards -Original Message- From: Robert Raszuk [mailto:rob...@raszuk.net] Sent: Wednesday, August 10, 2011 11:29 PM To: Harry Reynolds Cc: Keegan Holley; juniper-nsp@puck.nether.net Subject: Re: [j-nsp] load balancing in Route reflector scenario Hi Harry, default, differences in route preference cause a JUNI to prefer an IGP route while ios prefer the bgp routs over IGP. Let's make a clear distinction between preferring eBGP route versus iBGP route. Talking CSCO here eBGP admin distance is as you say 20 while iBGP as even the URL provided by yourself says it is 200. So keeping in mind that usually hot potato routing is a desired behaviour preferring EBGP learned path is highly recommended for a given prefix. If you say that JUNI is to prefer IGP route over BGP one I am sure you must be referring to IBGP and not EBGP, but this is exactly the same in both vendors. W/o this knob replacing a cisco with a juniper can result in previously advertised bgp routes no longer being advertised. I can rest assure you that this was not the main intention of this knob :) Cheers, R. I always thought that advertise-inactive was to make a juniper act like a cisco with regard to BGP route announcements, when, by default, differences in route preference cause a JUNI to prefer an IGP route while ios prefer the bgp routs over IGP. In junos, only the active route is readvertised/subject to export policy. With advertise-inactive you can make a juniper router, whose active route is an IGP route, advertise into BGP the best bgp path, which here is inactive due to the igp route being preferred. W/o this knob replacing a cisco with a juniper can result in previously advertised bgp routes no longer being advertised. From: http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080 094823.shtml eBGP 20 . . . OSPF 110 From: http://www.juniper.net/techpubs/software/junos/junos64/swconfig64-rout ing/html/protocols-overview4.html OSPF internal route 10 IS-IS Level 1 internal route 15 . . . BGP 170 HTHS. -Original Message- From: juniper-nsp-boun...@puck.nether.net [mailto:juniper-nsp-boun...@puck.nether.net] On Behalf Of Keegan Holley Sent: Wednesday, August 10, 2011 2:48 PM To: rob...@raszuk.net Cc: juniper-nsp@puck.nether.net Subject: Re: [j-nsp] load balancing in Route reflector scenario 2011/8/10 Robert Raszukrob...@raszuk.net Hi Keegan, I think the advertise inactive knob turns that off, but I don't know for sure because I've never tried it. I know it's not supported on cisco routers. The reason for it is the size of the BGP table. So if the table is 400k routes and you have 5 different ISP's and you advertise every route that would be 2M routes in the table. Since BGP doesn't allow multiple version of the same route in the routing table (separate from the BGP table where incoming routes are stored) you would still only use the original 400K the other 1.8M routes would just go unused unless you manipulated them some how. Advertise inactive is not about what get's advertised - it is about if the best path is advertised or not. And if is decided based on the check if the BGP path to be advertised is inserted in the RIB/FIB or not. Oh I see. I have never used that command so thanks. Most of the above example was what would happen if BGP advertised everything it learned instead of just the best path or the path in the routing table btw. By default Junos and IOS-XR advertise only those best path in BGP which actually are installed into forwarding. Advertising inactive knob will overwrite it. Wouldn't this lead to traffic being blackholed? If all the routes for a given destination are inactive would this still cause BGP to advertise a route for them? IOS classic/XE (for historical reasons) advertises all best paths from BGP table and to enforce it not to advertise what has not been installed into RIB/FIB there is knob called suppress inactive. Cheers, R. ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] load balancing in Route reflector scenario
Hi All, My be this info will help understand!! Juniper - Default Administrative Distance - preference Direct/Local : 0 Static : 5 RSVP : 7 Resource Reservation Protocol LDP : 9 Label Distribution Protocol OSPF internal route : 10 IS-IS Level 1 internal route : 15 IS-IS Level 2 internal route : 18 Default : 20 RIP : 100 RIPng : 100 PIM : 105 DVMRP : 110 Aggregate routes: 130 OSPF AS external routes : 150 IS-IS Level 1 external route : 160 IS-IS Level 2 external route : 165 BGP : 170 MSDP: 175 Cisco - Default Administrative Distance Routing Source Administrative Distance Connected interface or static route that identifies the outgoing interface rather than the next hop0 Static route 1 EIGRP summary route 5 External BGP 20 EIGRP 90 IGRP 100 OSPF 110 RIP 120 External EIGRP 170 Internal BGP 200 An unknown network 255 or infinity Cheers, Dusan On Thu, Aug 11, 2011 at 5:09 PM, Harry Reynolds ha...@juniper.net wrote: Juniper does not have a specific preference for ebgp vs ibgp. The active route selection process does prefer e over i, so in that regard IOS and JUNI are the same. Where in my message did I say IBGP? I was referring to an EBGP route vs an OSPF/IGP route. In which case the cisco will select the EBGP, and readvertise it downstream, while a JUNI will select the ospf version, and therefore, by default, not readvertise the BGP version. As such placing a juni into that spot results in a different set of bgp route advertisements, which again, stem from different global route preference. I can rest assure you that this was not the main intention of this knob :) Your statement above is incorrect. This is the intended use of the knob. Regards -Original Message- From: Robert Raszuk [mailto:rob...@raszuk.net] Sent: Wednesday, August 10, 2011 11:29 PM To: Harry Reynolds Cc: Keegan Holley; juniper-nsp@puck.nether.net Subject: Re: [j-nsp] load balancing in Route reflector scenario Hi Harry, default, differences in route preference cause a JUNI to prefer an IGP route while ios prefer the bgp routs over IGP. Let's make a clear distinction between preferring eBGP route versus iBGP route. Talking CSCO here eBGP admin distance is as you say 20 while iBGP as even the URL provided by yourself says it is 200. So keeping in mind that usually hot potato routing is a desired behaviour preferring EBGP learned path is highly recommended for a given prefix. If you say that JUNI is to prefer IGP route over BGP one I am sure you must be referring to IBGP and not EBGP, but this is exactly the same in both vendors. W/o this knob replacing a cisco with a juniper can result in previously advertised bgp routes no longer being advertised. I can rest assure you that this was not the main intention of this knob :) Cheers, R. I always thought that advertise-inactive was to make a juniper act like a cisco with regard to BGP route announcements, when, by default, differences in route preference cause a JUNI to prefer an IGP route while ios prefer the bgp routs over IGP. In junos, only the active route is readvertised/subject to export policy. With advertise-inactive you can make a juniper router, whose active route is an IGP route, advertise into BGP the best bgp path, which here is inactive due to the igp route being preferred. W/o this knob replacing a cisco with a juniper can result in previously advertised bgp routes no longer being advertised. From: http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080 094823.shtml eBGP 20 . . . OSPF 110 From: http://www.juniper.net/techpubs/software/junos/junos64/swconfig64-rout ing/html/protocols-overview4.html OSPF internal route 10 IS-IS Level 1 internal route 15 . . . BGP 170 HTHS. -Original Message- From: juniper-nsp-boun...@puck.nether.net [mailto:juniper-nsp-boun...@puck.nether.net] On Behalf Of Keegan Holley Sent: Wednesday, August 10, 2011 2:48 PM To: rob...@raszuk.net Cc: juniper-nsp@puck.nether.net Subject: Re: [j-nsp] load balancing in Route reflector scenario 2011/8/10 Robert Raszukrob...@raszuk.net Hi Keegan, I think the advertise inactive knob turns that off, but I don't know for sure because I've never tried it. I know it's not supported on cisco routers. The reason for it is the size of the BGP table. So if the table is 400k routes and you have 5 different ISP's and you advertise every route that would be 2M routes in the table. Since BGP doesn't allow multiple version
[j-nsp] load balancing in Route reflector scenario
Dear All I have a setup where I need to load balancing routes received from 2 RR in IPV4 environment (not VPN-IPV4) I have my PE (let's called PE1) connected to 2 RR (cluster), my destination subnet eg: 10.1.1.1/24 is behind 2 PE (PE-2 and PE3) which are also client of the same 2RR PE-2 and PE3 are sending the same route 10.1.1.1/24 to the RR , which as per normal behavior is selecting the best route to PE1 , My issue is that RR is always advertising the route 10.1.1.1/24 through PE2 (due to lower router id) as best path and I would like to load balanced it through PE2 and PE3 Anyone can recommend a way to load balance ? Unfortunately I dont have a lab to test any solution and there are live traffic on this ,so all I can do is guessing is whether the below 2 option would work or not. 2 option I have 1.So here I am trying to thinking about testing the multipath command under the RR configuration to see if I am receiving routes from both PE or not , 2. try to put all devices them in routing instance VRF , with the BGP configuration under it (both RR and client) , and RD configured in the VRF (but not putting any vpn family under bgp) so that it stays IPV4 routes , maybe I could cheat the RR to believe these are 2 differentes routes due to the RD, but dont know if this works or not . anyone has had similar issue and found a workaround ? does the 2 option above actually work or not ? thanks for any input ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] load balancing in Route reflector scenario
Not sure if others will have a better answer, but I don't think this is possible. As far as I know BGP doesn't support multi-pathing so there isn't a way to have two next hops used for the same prefix. You might be able to peer with a loopback address and use your IGP to create equal cost routes to the BGP loopback address. If you run mpls that obviously complicates things a bit. 2011/8/10 biwa net biwa...@gmail.com Dear All I have a setup where I need to load balancing routes received from 2 RR in IPV4 environment (not VPN-IPV4) I have my PE (let's called PE1) connected to 2 RR (cluster), my destination subnet eg: 10.1.1.1/24 is behind 2 PE (PE-2 and PE3) which are also client of the same 2RR PE-2 and PE3 are sending the same route 10.1.1.1/24 to the RR , which as per normal behavior is selecting the best route to PE1 , My issue is that RR is always advertising the route 10.1.1.1/24 through PE2 (due to lower router id) as best path and I would like to load balanced it through PE2 and PE3 Anyone can recommend a way to load balance ? Unfortunately I dont have a lab to test any solution and there are live traffic on this ,so all I can do is guessing is whether the below 2 option would work or not. 2 option I have 1.So here I am trying to thinking about testing the multipath command under the RR configuration to see if I am receiving routes from both PE or not , 2. try to put all devices them in routing instance VRF , with the BGP configuration under it (both RR and client) , and RD configured in the VRF (but not putting any vpn family under bgp) so that it stays IPV4 routes , maybe I could cheat the RR to believe these are 2 differentes routes due to the RD, but dont know if this works or not . anyone has had similar issue and found a workaround ? does the 2 option above actually work or not ? thanks for any input ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] load balancing in Route reflector scenario
Keegan, Look into add-path, something that is not supported in JUNOS yet, but will be sometime this year. http://tools.ietf.org/html/draft-walton-bgp-add-paths-06 http://www.nanog.org/meetings/nanog48/presentations/Tuesday/Ward_AddPath_N48.pdf http://www.juniper.net/us/en/local/pdf/whitepapers/2000345-en.pdf -Zaid On Wed, Aug 10, 2011 at 13:02, Keegan Holley keegan.hol...@sungard.comwrote: Not sure if others will have a better answer, but I don't think this is possible. As far as I know BGP doesn't support multi-pathing so there isn't a way to have two next hops used for the same prefix. You might be able to peer with a loopback address and use your IGP to create equal cost routes to the BGP loopback address. If you run mpls that obviously complicates things a bit. 2011/8/10 biwa net biwa...@gmail.com Dear All I have a setup where I need to load balancing routes received from 2 RR in IPV4 environment (not VPN-IPV4) I have my PE (let's called PE1) connected to 2 RR (cluster), my destination subnet eg: 10.1.1.1/24 is behind 2 PE (PE-2 and PE3) which are also client of the same 2RR PE-2 and PE3 are sending the same route 10.1.1.1/24 to the RR , which as per normal behavior is selecting the best route to PE1 , My issue is that RR is always advertising the route 10.1.1.1/24 through PE2 (due to lower router id) as best path and I would like to load balanced it through PE2 and PE3 Anyone can recommend a way to load balance ? Unfortunately I dont have a lab to test any solution and there are live traffic on this ,so all I can do is guessing is whether the below 2 option would work or not. 2 option I have 1.So here I am trying to thinking about testing the multipath command under the RR configuration to see if I am receiving routes from both PE or not , 2. try to put all devices them in routing instance VRF , with the BGP configuration under it (both RR and client) , and RD configured in the VRF (but not putting any vpn family under bgp) so that it stays IPV4 routes , maybe I could cheat the RR to believe these are 2 differentes routes due to the RD, but dont know if this works or not . anyone has had similar issue and found a workaround ? does the 2 option above actually work or not ? thanks for any input ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] load balancing in Route reflector scenario
Have you tried the advertise-inactive knob on the RR? I can't guarantee that this will work but it just might also advertise the route towards PE3 as well. Of course, if this works, then you would need to enable multipathing on PE1 accordingly. Stefan Fouant JNCIE-M, JNCIE-ER, JNCIE-SEC, JNCI Technical Trainer, Juniper Networks http://www.shortestpathfirst.net http://www.twitter.com/sfouant Sent from my iPad On Aug 10, 2011, at 2:44 PM, biwa net biwa...@gmail.com wrote: Dear All I have a setup where I need to load balancing routes received from 2 RR in IPV4 environment (not VPN-IPV4) I have my PE (let's called PE1) connected to 2 RR (cluster), my destination subnet eg: 10.1.1.1/24 is behind 2 PE (PE-2 and PE3) which are also client of the same 2RR PE-2 and PE3 are sending the same route 10.1.1.1/24 to the RR , which as per normal behavior is selecting the best route to PE1 , My issue is that RR is always advertising the route 10.1.1.1/24 through PE2 (due to lower router id) as best path and I would like to load balanced it through PE2 and PE3 Anyone can recommend a way to load balance ? Unfortunately I dont have a lab to test any solution and there are live traffic on this ,so all I can do is guessing is whether the below 2 option would work or not. 2 option I have 1.So here I am trying to thinking about testing the multipath command under the RR configuration to see if I am receiving routes from both PE or not , 2. try to put all devices them in routing instance VRF , with the BGP configuration under it (both RR and client) , and RD configured in the VRF (but not putting any vpn family under bgp) so that it stays IPV4 routes , maybe I could cheat the RR to believe these are 2 differentes routes due to the RD, but dont know if this works or not . anyone has had similar issue and found a workaround ? does the 2 option above actually work or not ? thanks for any input ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] load balancing in Route reflector scenario
just to clarify , you have : PE2 with 2 link , 1 to RR1 (let's call it link 1) and 1 to RR2 (link 2) PE3 with 2 link , 1 to RR1 (let's call it Link 3) and 1 to RR2 (link4) you could set local pref to link to PE2 to 150 (RR1 to PE2 will be preferred), and link 2 (PE2 to RR2) as standard 100 then set link 3 standard 100 (PE3 to RR1) but set link 4 with 150 (RR2 to PE3 will be preferred) then RR1 has prefered path via PE2 (via link 1 high local pref), RR2 have prefered path via PE3( via link 4 high local pref) , Each RR may advertise both route to PE1 then on PE1 , u need load balancing configured , I can't guarantee either , but need to be tested. On 10 August 2011 21:06, Stefan Fouant sfou...@shortestpathfirst.netwrote: Have you tried the advertise-inactive knob on the RR? I can't guarantee that this will work but it just might also advertise the route towards PE3 as well. Of course, if this works, then you would need to enable multipathing on PE1 accordingly. Stefan Fouant JNCIE-M, JNCIE-ER, JNCIE-SEC, JNCI Technical Trainer, Juniper Networks http://www.shortestpathfirst.net http://www.twitter.com/sfouant Sent from my iPad On Aug 10, 2011, at 2:44 PM, biwa net biwa...@gmail.com wrote: Dear All I have a setup where I need to load balancing routes received from 2 RR in IPV4 environment (not VPN-IPV4) I have my PE (let's called PE1) connected to 2 RR (cluster), my destination subnet eg: 10.1.1.1/24 is behind 2 PE (PE-2 and PE3) which are also client of the same 2RR PE-2 and PE3 are sending the same route 10.1.1.1/24 to the RR , which as per normal behavior is selecting the best route to PE1 , My issue is that RR is always advertising the route 10.1.1.1/24 through PE2 (due to lower router id) as best path and I would like to load balanced it through PE2 and PE3 Anyone can recommend a way to load balance ? Unfortunately I dont have a lab to test any solution and there are live traffic on this ,so all I can do is guessing is whether the below 2 option would work or not. 2 option I have 1.So here I am trying to thinking about testing the multipath command under the RR configuration to see if I am receiving routes from both PE or not , 2. try to put all devices them in routing instance VRF , with the BGP configuration under it (both RR and client) , and RD configured in the VRF (but not putting any vpn family under bgp) so that it stays IPV4 routes , maybe I could cheat the RR to believe these are 2 differentes routes due to the RD, but dont know if this works or not . anyone has had similar issue and found a workaround ? does the 2 option above actually work or not ? thanks for any input ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp -- Humair ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] load balancing in Route reflector scenario
I thought advertise inactive just configured the routers to advertise the entire BGP RIB instead of only advertising the routes in the routing-table. How would you configure multipathing once the routes were there? 2011/8/10 Stefan Fouant sfou...@shortestpathfirst.net Have you tried the advertise-inactive knob on the RR? I can't guarantee that this will work but it just might also advertise the route towards PE3 as well. Of course, if this works, then you would need to enable multipathing on PE1 accordingly. Stefan Fouant JNCIE-M, JNCIE-ER, JNCIE-SEC, JNCI Technical Trainer, Juniper Networks http://www.shortestpathfirst.net http://www.twitter.com/sfouant Sent from my iPad On Aug 10, 2011, at 2:44 PM, biwa net biwa...@gmail.com wrote: Dear All I have a setup where I need to load balancing routes received from 2 RR in IPV4 environment (not VPN-IPV4) I have my PE (let's called PE1) connected to 2 RR (cluster), my destination subnet eg: 10.1.1.1/24 is behind 2 PE (PE-2 and PE3) which are also client of the same 2RR PE-2 and PE3 are sending the same route 10.1.1.1/24 to the RR , which as per normal behavior is selecting the best route to PE1 , My issue is that RR is always advertising the route 10.1.1.1/24 through PE2 (due to lower router id) as best path and I would like to load balanced it through PE2 and PE3 Anyone can recommend a way to load balance ? Unfortunately I dont have a lab to test any solution and there are live traffic on this ,so all I can do is guessing is whether the below 2 option would work or not. 2 option I have 1.So here I am trying to thinking about testing the multipath command under the RR configuration to see if I am receiving routes from both PE or not , 2. try to put all devices them in routing instance VRF , with the BGP configuration under it (both RR and client) , and RD configured in the VRF (but not putting any vpn family under bgp) so that it stays IPV4 routes , maybe I could cheat the RR to believe these are 2 differentes routes due to the RD, but dont know if this works or not . anyone has had similar issue and found a workaround ? does the 2 option above actually work or not ? thanks for any input ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] load balancing in Route reflector scenario
Hello, On this link http://goo.gl/6FgnZ from Cisco site you can find the below quote: Route Reflector Limitation When multiple iBGP paths installed in a routing table, a route reflector will advertise only one paths (next hop). If a router is behind a route reflector, all routers that are connected to multihomed sites will not be advertised unless a different route distinguisher is configured for each VRF. To be honest I don't why is like this, but I think that with 'multipath' it won't work. HTH On Wed, Aug 10, 2011 at 23:32, Humair Ali humair.s@gmail.com wrote: just to clarify , you have : PE2 with 2 link , 1 to RR1 (let's call it link 1) and 1 to RR2 (link 2) PE3 with 2 link , 1 to RR1 (let's call it Link 3) and 1 to RR2 (link4) you could set local pref to link to PE2 to 150 (RR1 to PE2 will be preferred), and link 2 (PE2 to RR2) as standard 100 then set link 3 standard 100 (PE3 to RR1) but set link 4 with 150 (RR2 to PE3 will be preferred) then RR1 has prefered path via PE2 (via link 1 high local pref), RR2 have prefered path via PE3( via link 4 high local pref) , Each RR may advertise both route to PE1 then on PE1 , u need load balancing configured , I can't guarantee either , but need to be tested. On 10 August 2011 21:06, Stefan Fouant sfou...@shortestpathfirst.net wrote: Have you tried the advertise-inactive knob on the RR? I can't guarantee that this will work but it just might also advertise the route towards PE3 as well. Of course, if this works, then you would need to enable multipathing on PE1 accordingly. Stefan Fouant JNCIE-M, JNCIE-ER, JNCIE-SEC, JNCI Technical Trainer, Juniper Networks http://www.shortestpathfirst.net http://www.twitter.com/sfouant Sent from my iPad On Aug 10, 2011, at 2:44 PM, biwa net biwa...@gmail.com wrote: Dear All I have a setup where I need to load balancing routes received from 2 RR in IPV4 environment (not VPN-IPV4) I have my PE (let's called PE1) connected to 2 RR (cluster), my destination subnet eg: 10.1.1.1/24 is behind 2 PE (PE-2 and PE3) which are also client of the same 2RR PE-2 and PE3 are sending the same route 10.1.1.1/24 to the RR , which as per normal behavior is selecting the best route to PE1 , My issue is that RR is always advertising the route 10.1.1.1/24through PE2 (due to lower router id) as best path and I would like to load balanced it through PE2 and PE3 Anyone can recommend a way to load balance ? Unfortunately I dont have a lab to test any solution and there are live traffic on this ,so all I can do is guessing is whether the below 2 option would work or not. 2 option I have 1.So here I am trying to thinking about testing the multipath command under the RR configuration to see if I am receiving routes from both PE or not , 2. try to put all devices them in routing instance VRF , with the BGP configuration under it (both RR and client) , and RD configured in the VRF (but not putting any vpn family under bgp) so that it stays IPV4 routes , maybe I could cheat the RR to believe these are 2 differentes routes due to the RD, but dont know if this works or not . anyone has had similar issue and found a workaround ? does the 2 option above actually work or not ? thanks for any input ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp -- Humair ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp -- Best Regards! Ivan Ivanov ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] load balancing in Route reflector scenario
2011/8/10 Humair Ali humair.s@gmail.com just to clarify , you have : PE2 with 2 link , 1 to RR1 (let's call it link 1) and 1 to RR2 (link 2) PE3 with 2 link , 1 to RR1 (let's call it Link 3) and 1 to RR2 (link4) you could set local pref to link to PE2 to 150 (RR1 to PE2 will be preferred), and link 2 (PE2 to RR2) as standard 100 then set link 3 standard 100 (PE3 to RR1) but set link 4 with 150 (RR2 to PE3 will be preferred) local pref isn't link specific and neither are the BGP peerings. In other words if you have two links to the same RR you would normally only have one peering. If you had multiple, you would still only choose a single route advertised by a single route reflector even though you are changing the local pref several times. then RR1 has prefered path via PE2 (via link 1 high local pref), RR2 have prefered path via PE3( via link 4 high local pref) , Each RR may advertise both route to PE1 The route reflector isn't in the forwarding path most of the time. So the PE's learn each other's routes through the route reflectors but forward directly to each other or to other P routers. On 10 August 2011 21:06, Stefan Fouant sfou...@shortestpathfirst.netwrote: Have you tried the advertise-inactive knob on the RR? I can't guarantee that this will work but it just might also advertise the route towards PE3 as well. Of course, if this works, then you would need to enable multipathing on PE1 accordingly. Stefan Fouant JNCIE-M, JNCIE-ER, JNCIE-SEC, JNCI Technical Trainer, Juniper Networks http://www.shortestpathfirst.net http://www.twitter.com/sfouant Sent from my iPad On Aug 10, 2011, at 2:44 PM, biwa net biwa...@gmail.com wrote: Dear All I have a setup where I need to load balancing routes received from 2 RR in IPV4 environment (not VPN-IPV4) I have my PE (let's called PE1) connected to 2 RR (cluster), my destination subnet eg: 10.1.1.1/24 is behind 2 PE (PE-2 and PE3) which are also client of the same 2RR PE-2 and PE3 are sending the same route 10.1.1.1/24 to the RR , which as per normal behavior is selecting the best route to PE1 , My issue is that RR is always advertising the route 10.1.1.1/24through PE2 (due to lower router id) as best path and I would like to load balanced it through PE2 and PE3 Anyone can recommend a way to load balance ? Unfortunately I dont have a lab to test any solution and there are live traffic on this ,so all I can do is guessing is whether the below 2 option would work or not. 2 option I have 1.So here I am trying to thinking about testing the multipath command under the RR configuration to see if I am receiving routes from both PE or not , 2. try to put all devices them in routing instance VRF , with the BGP configuration under it (both RR and client) , and RD configured in the VRF (but not putting any vpn family under bgp) so that it stays IPV4 routes , maybe I could cheat the RR to believe these are 2 differentes routes due to the RD, but dont know if this works or not . anyone has had similar issue and found a workaround ? does the 2 option above actually work or not ? thanks for any input ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp -- Humair ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] load balancing in Route reflector scenario
Hi Keegan, I thought advertise inactive just configured the routers to advertise the entire BGP RIB instead of only advertising the routes in the routing-table. Nope. BGP advertises by default single best path. Any subsequent advertisement will be an implicit withdraw. Hi Humair, Per RR different local policy is a valid workaround int he case as reported by biwa. But care must be taken that the network either supports end to end encapsulation (example: mpls) or that all routers on the way will get the same paths. Hi Biwa, 1. The easiest option is to get rid of RR .. just do full IBGP mesh. I know large networks doing it today :) 2. The other option is to put RR in the data path and enable multipath in it. The end effect will be the same as enabling it on PE1. 3. To signal both paths to PE1 from RRs you need either add-paths or diverse-path. Add-paths will require support on PE1 while diverse-path will not. And depending on the choice of RR diverse-path is available today in some implementations :-) 4. Another way is to do ghost loopback (aka anycast next hop self) on PE2 and PE3 and let the IGP load-balance across both PEs. Works well if you have symmetry of IGP and routes of both PE2 and PE3. Cheers, R. ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] load balancing in Route reflector scenario
I think the advertise inactive knob turns that off, but I don't know for sure because I've never tried it. I know it's not supported on cisco routers. The reason for it is the size of the BGP table. So if the table is 400k routes and you have 5 different ISP's and you advertise every route that would be 2M routes in the table. Since BGP doesn't allow multiple version of the same route in the routing table (separate from the BGP table where incoming routes are stored) you would still only use the original 400K the other 1.8M routes would just go unused unless you manipulated them some how. 2011/8/10 Ivan Ivanov ivanov.i...@gmail.com Hello, On this link http://goo.gl/6FgnZ from Cisco site you can find the below quote: Route Reflector Limitation When multiple iBGP paths installed in a routing table, a route reflector will advertise only one paths (next hop). If a router is behind a route reflector, all routers that are connected to multihomed sites will not be advertised unless a different route distinguisher is configured for each VRF. To be honest I don't why is like this, but I think that with 'multipath' it won't work. HTH On Wed, Aug 10, 2011 at 23:32, Humair Ali humair.s@gmail.com wrote: just to clarify , you have : PE2 with 2 link , 1 to RR1 (let's call it link 1) and 1 to RR2 (link 2) PE3 with 2 link , 1 to RR1 (let's call it Link 3) and 1 to RR2 (link4) you could set local pref to link to PE2 to 150 (RR1 to PE2 will be preferred), and link 2 (PE2 to RR2) as standard 100 then set link 3 standard 100 (PE3 to RR1) but set link 4 with 150 (RR2 to PE3 will be preferred) then RR1 has prefered path via PE2 (via link 1 high local pref), RR2 have prefered path via PE3( via link 4 high local pref) , Each RR may advertise both route to PE1 then on PE1 , u need load balancing configured , I can't guarantee either , but need to be tested. On 10 August 2011 21:06, Stefan Fouant sfou...@shortestpathfirst.net wrote: Have you tried the advertise-inactive knob on the RR? I can't guarantee that this will work but it just might also advertise the route towards PE3 as well. Of course, if this works, then you would need to enable multipathing on PE1 accordingly. Stefan Fouant JNCIE-M, JNCIE-ER, JNCIE-SEC, JNCI Technical Trainer, Juniper Networks http://www.shortestpathfirst.net http://www.twitter.com/sfouant Sent from my iPad On Aug 10, 2011, at 2:44 PM, biwa net biwa...@gmail.com wrote: Dear All I have a setup where I need to load balancing routes received from 2 RR in IPV4 environment (not VPN-IPV4) I have my PE (let's called PE1) connected to 2 RR (cluster), my destination subnet eg: 10.1.1.1/24 is behind 2 PE (PE-2 and PE3) which are also client of the same 2RR PE-2 and PE3 are sending the same route 10.1.1.1/24 to the RR , which as per normal behavior is selecting the best route to PE1 , My issue is that RR is always advertising the route 10.1.1.1/24through PE2 (due to lower router id) as best path and I would like to load balanced it through PE2 and PE3 Anyone can recommend a way to load balance ? Unfortunately I dont have a lab to test any solution and there are live traffic on this ,so all I can do is guessing is whether the below 2 option would work or not. 2 option I have 1.So here I am trying to thinking about testing the multipath command under the RR configuration to see if I am receiving routes from both PE or not , 2. try to put all devices them in routing instance VRF , with the BGP configuration under it (both RR and client) , and RD configured in the VRF (but not putting any vpn family under bgp) so that it stays IPV4 routes , maybe I could cheat the RR to believe these are 2 differentes routes due to the RD, but dont know if this works or not . anyone has had similar issue and found a workaround ? does the 2 option above actually work or not ? thanks for any input ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp -- Humair ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp -- Best Regards! Ivan Ivanov ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp ___ juniper-nsp mailing list juniper-nsp@puck.nether.net
Re: [j-nsp] load balancing in Route reflector scenario
Hi Keegan, I think the advertise inactive knob turns that off, but I don't know for sure because I've never tried it. I know it's not supported on cisco routers. The reason for it is the size of the BGP table. So if the table is 400k routes and you have 5 different ISP's and you advertise every route that would be 2M routes in the table. Since BGP doesn't allow multiple version of the same route in the routing table (separate from the BGP table where incoming routes are stored) you would still only use the original 400K the other 1.8M routes would just go unused unless you manipulated them some how. Advertise inactive is not about what get's advertised - it is about if the best path is advertised or not. And if is decided based on the check if the BGP path to be advertised is inserted in the RIB/FIB or not. By default Junos and IOS-XR advertise only those best path in BGP which actually are installed into forwarding. Advertising inactive knob will overwrite it. IOS classic/XE (for historical reasons) advertises all best paths from BGP table and to enforce it not to advertise what has not been installed into RIB/FIB there is knob called suppress inactive. Cheers, R. ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] load balancing in Route reflector scenario
2011/8/10 Robert Raszuk rob...@raszuk.net Hi Keegan, I think the advertise inactive knob turns that off, but I don't know for sure because I've never tried it. I know it's not supported on cisco routers. The reason for it is the size of the BGP table. So if the table is 400k routes and you have 5 different ISP's and you advertise every route that would be 2M routes in the table. Since BGP doesn't allow multiple version of the same route in the routing table (separate from the BGP table where incoming routes are stored) you would still only use the original 400K the other 1.8M routes would just go unused unless you manipulated them some how. Advertise inactive is not about what get's advertised - it is about if the best path is advertised or not. And if is decided based on the check if the BGP path to be advertised is inserted in the RIB/FIB or not. Oh I see. I have never used that command so thanks. Most of the above example was what would happen if BGP advertised everything it learned instead of just the best path or the path in the routing table btw. By default Junos and IOS-XR advertise only those best path in BGP which actually are installed into forwarding. Advertising inactive knob will overwrite it. Wouldn't this lead to traffic being blackholed? If all the routes for a given destination are inactive would this still cause BGP to advertise a route for them? IOS classic/XE (for historical reasons) advertises all best paths from BGP table and to enforce it not to advertise what has not been installed into RIB/FIB there is knob called suppress inactive. Cheers, R. ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] load balancing in Route reflector scenario
Hi Keegan, By default Junos and IOS-XR advertise only those best path in BGP which actually are installed into forwarding. Advertising inactive knob will overwrite it. Wouldn't this lead to traffic being blackholed? If all the routes for a given destination are inactive would this still cause BGP to advertise a route for them? Nope ... there can be other producers of the same route (OSPF, ISIS, STATIC) which will be in the RIB. If not there is always next step - less specific route to be used. So there are some valid cases where you may want to attract by BGP all traffic, but switch it according by your own policy and not by BGP decision. Cheers, R. ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] load balancing in Route reflector scenario
I'd consider preceding certain route ranges across the links. Prefer a range of routes on each link. Depending how you write your filters, you'll be able to tune things a bit as well as keep redundancy. The return path can be more difficult, but I find that as prepends or more specific route advertisements work well. Will O'Brien On Aug 10, 2011, at 4:53 PM, Robert Raszuk rob...@raszuk.net wrote: Hi Keegan, By default Junos and IOS-XR advertise only those best path in BGP which actually are installed into forwarding. Advertising inactive knob will overwrite it. Wouldn't this lead to traffic being blackholed? If all the routes for a given destination are inactive would this still cause BGP to advertise a route for them? Nope ... there can be other producers of the same route (OSPF, ISIS, STATIC) which will be in the RIB. If not there is always next step - less specific route to be used. So there are some valid cases where you may want to attract by BGP all traffic, but switch it according by your own policy and not by BGP decision. Cheers, R. ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] load balancing in Route reflector scenario
I always thought that advertise-inactive was to make a juniper act like a cisco with regard to BGP route announcements, when, by default, differences in route preference cause a JUNI to prefer an IGP route while ios prefer the bgp routs over IGP. In junos, only the active route is readvertised/subject to export policy. With advertise-inactive you can make a juniper router, whose active route is an IGP route, advertise into BGP the best bgp path, which here is inactive due to the igp route being preferred. W/o this knob replacing a cisco with a juniper can result in previously advertised bgp routes no longer being advertised. From: http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094823.shtml eBGP 20 . . . OSPF 110 From: http://www.juniper.net/techpubs/software/junos/junos64/swconfig64-routing/html/protocols-overview4.html OSPF internal route 10 IS-IS Level 1 internal route 15 . . . BGP 170 HTHS. -Original Message- From: juniper-nsp-boun...@puck.nether.net [mailto:juniper-nsp-boun...@puck.nether.net] On Behalf Of Keegan Holley Sent: Wednesday, August 10, 2011 2:48 PM To: rob...@raszuk.net Cc: juniper-nsp@puck.nether.net Subject: Re: [j-nsp] load balancing in Route reflector scenario 2011/8/10 Robert Raszuk rob...@raszuk.net Hi Keegan, I think the advertise inactive knob turns that off, but I don't know for sure because I've never tried it. I know it's not supported on cisco routers. The reason for it is the size of the BGP table. So if the table is 400k routes and you have 5 different ISP's and you advertise every route that would be 2M routes in the table. Since BGP doesn't allow multiple version of the same route in the routing table (separate from the BGP table where incoming routes are stored) you would still only use the original 400K the other 1.8M routes would just go unused unless you manipulated them some how. Advertise inactive is not about what get's advertised - it is about if the best path is advertised or not. And if is decided based on the check if the BGP path to be advertised is inserted in the RIB/FIB or not. Oh I see. I have never used that command so thanks. Most of the above example was what would happen if BGP advertised everything it learned instead of just the best path or the path in the routing table btw. By default Junos and IOS-XR advertise only those best path in BGP which actually are installed into forwarding. Advertising inactive knob will overwrite it. Wouldn't this lead to traffic being blackholed? If all the routes for a given destination are inactive would this still cause BGP to advertise a route for them? IOS classic/XE (for historical reasons) advertises all best paths from BGP table and to enforce it not to advertise what has not been installed into RIB/FIB there is knob called suppress inactive. Cheers, R. ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] load balancing in Route reflector scenario
2011/8/10 Robert Raszuk rob...@raszuk.net Hi Keegan, By default Junos and IOS-XR advertise only those best path in BGP which actually are installed into forwarding. Advertising inactive knob will overwrite it. Wouldn't this lead to traffic being blackholed? If all the routes for a given destination are inactive would this still cause BGP to advertise a route for them? Nope ... there can be other producers of the same route (OSPF, ISIS, STATIC) which will be in the RIB. If not there is always next step - less specific route to be used. I suppose there's a use for this or the feature wouldn't exist, but why would you have a route in the IGP that's not in BGP but still needs to receive traffic from routers running an IGP and BGP but not learning the route from the IGP. Why not just import the route(s) into BGP. It just seems like this command may cause unexpected behavior to add features that can be configured in a more graceful manner. So there are some valid cases where you may want to attract by BGP all traffic, but switch it according by your own policy and not by BGP decision. Cheers, R. ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
