Re: BGP Route Reflectors [7:66488]
At 04:52 PM 3/31/2003 +, \"\"[EMAIL PROTECTED]"\" wrote: >All, > >Please can someone clear this up for me, if you have the time. > >IBGP peers do not have to be physically connected to one another, as long as >an IGP (most preferably) is running between them. In most cases the routers are not adjacent and certainly do not need to be. Half the reason one runs an IGP in an ISP is for loopback reachability support for IBGP peering. Such a demand would put pretty expensive topological demands on a network. >On page 128 (paragraph 1) of the Routing TCP/IP Volume 2 book, it says the >following about route reflectors and clients :- >"The clients have physical connections to each of the route reflectors, and >they peer to each" This may relate only to the diagram in question. >I assume that each client in a iBGP domain, does not need to share a >physical data-link to each RR? Correct. >Many thx. (maybe im just tired from studying all weekend). > >Regards, >Ken > > > >For more information about Barclays Capital, please >visit our web site at http://www.barcap.com. > > >Internet communications are not secure and therefore the Barclays >Group does not accept legal responsibility for the contents of this >message. Although the Barclays Group operates anti-virus programmes, >it does not accept responsibility for any damage whatsoever that is >caused by viruses being passed. Any views or opinions presented are >solely those of the author and do not necessarily represent those of the >Barclays Group. Replies to this email may be monitored by the Barclays >Group for operational or business reasons. > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=66573&t=66488 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: BGP Route Reflectors [7:66488]
Wellthat is what the book says. Try it out on your own lab and you will see that a Route-reflector client does not have to be directly connected to the Route-reflector for it to work. Just tried it in my home lab and it works, the client is 3 routers away. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=66564&t=66488 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
BGP Route Reflectors [7:66488]
All, Please can someone clear this up for me, if you have the time. IBGP peers do not have to be physically connected to one another, as long as an IGP (most preferably) is running between them. On page 128 (paragraph 1) of the Routing TCP/IP Volume 2 book, it says the following about route reflectors and clients :- "The clients have physical connections to each of the route reflectors, and they peer to each" I assume that each client in a iBGP domain, does not need to share a physical data-link to each RR? Many thx. (maybe im just tired from studying all weekend). Regards, Ken For more information about Barclays Capital, please visit our web site at http://www.barcap.com. Internet communications are not secure and therefore the Barclays Group does not accept legal responsibility for the contents of this message. Although the Barclays Group operates anti-virus programmes, it does not accept responsibility for any damage whatsoever that is caused by viruses being passed. Any views or opinions presented are solely those of the author and do not necessarily represent those of the Barclays Group. Replies to this email may be monitored by the Barclays Group for operational or business reasons. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=66558&t=66488 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: BGP Route Reflectors [7:66488]
Thx to all who replied. Make sense now :)) Beers to all! -Original Message- From: The Long and Winding Road [mailto:[EMAIL PROTECTED] Sent: 31 March 2003 05:33 To: [EMAIL PROTECTED] Subject: Re: BGP Route Reflectors [7:66488] ""Mike Martins"" wrote in message news:[EMAIL PROTECTED] > Yes, EBGP multihop is between different AS's, that is a different > setup, it > must also have a way of reaching across the hops, an IGP. nope - works just fine for iBGP as well. > > On a IBGP you can have a hop across ie 5 routers in a IBGP peering session. ?? anyBGP assumes it's neighbor is directly connected - i.e. on the same segment. The EBGP-multihop command changes the TTL to whatever the configured hop count is. ( default 255 ) Refer to RFC 1771 for the specification. > As long as the IGP can reach the other peer it will work. Also, the > full mesh requirement of IBGP is in logical and not physical links. In > other words if you had 5 routers fully meshed each router would need 4 > neighbour statments. And then consider the amount of BGP updates > running to and fro, that is why route-reflectors are used, to minimize > peering sessions. different issue. For more information about Barclays Capital, please visit our web site at http://www.barcap.com. Internet communications are not secure and therefore the Barclays Group does not accept legal responsibility for the contents of this message. Although the Barclays Group operates anti-virus programmes, it does not accept responsibility for any damage whatsoever that is caused by viruses being passed. Any views or opinions presented are solely those of the author and do not necessarily represent those of the Barclays Group. Replies to this email may be monitored by the Barclays Group for operational or business reasons. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=66542&t=66488 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: BGP Route Reflectors [7:66488]
""Mike Martins"" wrote in message news:[EMAIL PROTECTED] > Yes, EBGP multihop is between different AS's, that is a different setup, it > must also have a way of reaching across the hops, an IGP. nope - works just fine for iBGP as well. > > On a IBGP you can have a hop across ie 5 routers in a IBGP peering session. ?? anyBGP assumes it's neighbor is directly connected - i.e. on the same segment. The EBGP-multihop command changes the TTL to whatever the configured hop count is. ( default 255 ) Refer to RFC 1771 for the specification. > As long as the IGP can reach the other peer it will work. Also, the full > mesh requirement of IBGP is in logical and not physical links. In other > words if you had 5 routers fully meshed each router would need 4 neighbour > statments. And then consider the amount of BGP updates running to and fro, > that is why route-reflectors are used, to minimize peering sessions. different issue. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=66533&t=66488 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: BGP Route Reflectors [7:66488]
Yes, EBGP multihop is between different AS's, that is a different setup, it must also have a way of reaching across the hops, an IGP. On a IBGP you can have a hop across ie 5 routers in a IBGP peering session. As long as the IGP can reach the other peer it will work. Also, the full mesh requirement of IBGP is in logical and not physical links. In other words if you had 5 routers fully meshed each router would need 4 neighbour statments. And then consider the amount of BGP updates running to and fro, that is why route-reflectors are used, to minimize peering sessions. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=66516&t=66488 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: BGP Route Reflectors [7:66488]
The Long and Winding Road wrote: > > wrote in message > news:[EMAIL PROTECTED] > > All, > > > > Please can someone clear this up for me, if you have the time. > > > > IBGP peers do not have to be physically connected to one > another, as long > as > > an IGP (most preferably) is running between them. > > > nope. direct connect is preferred, but nope - don't have to be > > > > > > On page 128 (paragraph 1) of the Routing TCP/IP Volume 2 > book, it says the > > following about route reflectors and clients :- > > "The clients have physical connections to each of the route > reflectors, > and > > they peer to each" > > preferred but not necessary. that's why there is an "neighbor > ebgp-multihop" I thought "ebgp-multihop" was for neighbors in different AS's ? Going right now to check it on the command reference ... > command :-> > > > > > > I assume that each client in a iBGP domain, does not need to > share a > > physical data-link to each RR? > > > nope > > > > > Many thx. (maybe im just tired from studying all weekend). > > > > Regards, > > Ken > > > > > > > > > For more information about Barclays Capital, please > > visit our web site at http://www.barcap.com. > > > > > > Internet communications are not secure and therefore the > Barclays > > Group does not accept legal responsibility for the contents > of this > > message. Although the Barclays Group operates anti-virus > programmes, > > it does not accept responsibility for any damage whatsoever > that is > > caused by viruses being passed. Any views or opinions > presented are > > solely those of the author and do not necessarily represent > those of the > > Barclays Group. Replies to this email may be monitored by > the Barclays > > Group for operational or business reasons. > > > > > > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=66514&t=66488 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: BGP Route Reflectors [7:66488]
A practise that is becoming quite common is running BGP on the edges of an AS only. It is a waste for a router in the core to have a full internet table. The Core could then comprise of ie MPLS which would optimize the traffic flows. I cannot remember which book I used but when I was studying for the CCNP I read somewhere that IBGP routes have to be 'physically connected', this is untrue of course. As long as the IGP can reach the IBGP peer it is fine. The problem is that these misinterpretations stick. For a month or so before I was corrected I actually thought that a physical connection was a requirement. There is also something else to consider; the way one book I read worded a section on Route-reflectors and Confederations made it sound like you could only use either or, not both. This is untrue of course, you can use Route-reflectors inside a confederation. Just a note. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=66510&t=66488 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: BGP Route Reflectors [7:66488]
Ken, Technically speaking, even eBGP has the ability to peer with neighbors that aren't directly connected. Typically, eBGP peers will have diect physical connectivity, whereas iBGP peers are part of the same AS, as long as a route/path exist to that peer, connectivity shouldn't be a problem. When you address this issue, think of the requirement for BGP to be sync'd with the IGP for route information to be advertised. As well as the limitations/features of the peering relationship from one AS to another, or devices within the same AS. HTH Nigel - Original Message - From: To: Sent: Sunday, March 30, 2003 9:10 AM Subject: BGP Route Reflectors [7:66488] > All, > > Please can someone clear this up for me, if you have the time. > > IBGP peers do not have to be physically connected to one another, as long as > an IGP (most preferably) is running between them. > > On page 128 (paragraph 1) of the Routing TCP/IP Volume 2 book, it says the > following about route reflectors and clients :- > "The clients have physical connections to each of the route reflectors, and > they peer to each" > > I assume that each client in a iBGP domain, does not need to share a > physical data-link to each RR? > > Many thx. (maybe im just tired from studying all weekend). > > Regards, > Ken > > > > For more information about Barclays Capital, please > visit our web site at http://www.barcap.com. > > > Internet communications are not secure and therefore the Barclays > Group does not accept legal responsibility for the contents of this > message. Although the Barclays Group operates anti-virus programmes, > it does not accept responsibility for any damage whatsoever that is > caused by viruses being passed. Any views or opinions presented are > solely those of the author and do not necessarily represent those of the > Barclays Group. Replies to this email may be monitored by the Barclays > Group for operational or business reasons. > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=66497&t=66488 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: BGP Route Reflectors [7:66488]
wrote in message news:[EMAIL PROTECTED] > All, > > Please can someone clear this up for me, if you have the time. > > IBGP peers do not have to be physically connected to one another, as long as > an IGP (most preferably) is running between them. nope. direct connect is preferred, but nope - don't have to be > > On page 128 (paragraph 1) of the Routing TCP/IP Volume 2 book, it says the > following about route reflectors and clients :- > "The clients have physical connections to each of the route reflectors, and > they peer to each" preferred but not necessary. that's why there is an "neighbor ebgp-multihop" command :-> > > I assume that each client in a iBGP domain, does not need to share a > physical data-link to each RR? nope > > Many thx. (maybe im just tired from studying all weekend). > > Regards, > Ken > > > > For more information about Barclays Capital, please > visit our web site at http://www.barcap.com. > > > Internet communications are not secure and therefore the Barclays > Group does not accept legal responsibility for the contents of this > message. Although the Barclays Group operates anti-virus programmes, > it does not accept responsibility for any damage whatsoever that is > caused by viruses being passed. Any views or opinions presented are > solely those of the author and do not necessarily represent those of the > Barclays Group. Replies to this email may be monitored by the Barclays > Group for operational or business reasons. > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=66493&t=66488 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
BGP Route Reflectors [7:66488]
All, Please can someone clear this up for me, if you have the time. IBGP peers do not have to be physically connected to one another, as long as an IGP (most preferably) is running between them. On page 128 (paragraph 1) of the Routing TCP/IP Volume 2 book, it says the following about route reflectors and clients :- "The clients have physical connections to each of the route reflectors, and they peer to each" I assume that each client in a iBGP domain, does not need to share a physical data-link to each RR? Many thx. (maybe im just tired from studying all weekend). Regards, Ken For more information about Barclays Capital, please visit our web site at http://www.barcap.com. Internet communications are not secure and therefore the Barclays Group does not accept legal responsibility for the contents of this message. Although the Barclays Group operates anti-virus programmes, it does not accept responsibility for any damage whatsoever that is caused by viruses being passed. Any views or opinions presented are solely those of the author and do not necessarily represent those of the Barclays Group. Replies to this email may be monitored by the Barclays Group for operational or business reasons. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=66488&t=66488 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
