In a straight comparison, doing the NULL route is
handled more efficiently on the router as its just standard
L3 forwarding. If you do an ACL instead, the router has to
do additional processing on the packet.
If you're running something like a GSR or 7609 and the right
LC where ACLs are handled
Yup, it is a traffic engineering (service specific routing)
problem. MPLS TE might be one way to solve this.I've
honestly not looked at what it would take to get MPLS to
run in this environment.However, enabling MPLS on the
network would be a major undertaking so I've been looking at
I'm considering a routing architecture where devices in the
network would run ~3 OSPF routing processes.
I think each routing process will be handling the routing
of non-overlapping address blocks and thus the routes they
give to the forwarding table should be disjoint.
However, I'd like to
feel free to point
out why these wouldn't work in your case.
Thanks,
Zsombor
p b wrote:
Using multiple processes might provide a way to implement
policy at the link level. Typically, when one thinks of
policy,
one thinks of BGP. But what if your policy requires the
ability
at the
other options, I am not sure this is the worst one... :)
Thanks,
Zsombor
p b wrote:
Here's some more detail.
Yes, assume the destination address (networks) represent
the corresponding service.
This is an existing production network where OSPF and iBGP are
already in use
feel free to point
out why these wouldn't work in your case.
Thanks,
Zsombor
p b wrote:
Using multiple processes might provide a way to implement
policy at the link level. Typically, when one thinks of
policy,
one thinks of BGP. But what if your policy requires the
ability
feel free to point
out why these wouldn't work in your case.
Thanks,
Zsombor
p b wrote:
Using multiple processes might provide a way to implement
policy at the link level. Typically, when one thinks of
policy,
one thinks of BGP. But what if your policy requires the
ability
Howard C. Berkowitz wrote:
Significant interest in Asia.
Selected industries: HDTV, 3G wireless, new generation air
traffic control
HDTV? Do you have any thoughts or pointers as to why HDTV
would be looking at v6?
Thanks
Message Posted at:
p b wrote:
I'm considering a routing architecture where devices in the
network would run ~3 OSPF routing processes.
I think each routing process will be handling the routing
of non-overlapping address blocks and thus the routes they
give to the forwarding table should be disjoint
Not sure what filtering capabilities you have on the switch,
but you might be able to set all of the subscriber facing
ports to block the forwarding out of DHCP DISCOVERs and REBINDS
requests. I forget the details, but you can determine the
directionality of the DHCP requests (DISCOVERs/REBINDs
terminate iBGP sessions on
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7i=73339t=73305
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The answer given seems a little thin. Here's how I understand
this to work. When a router wants to join (*, G), it either
needs to know the IP of the rendezvous point (RP) or a source
generating the mulitcast traffic. Until the tree to the RP is
built, the router only knows about the RP IP
dre wrote:
I, personally, do not want to get heavily into it. It's not
mature
technology, and it's all bad, IMO. There are a few solid
technologies...and they are mostly the ones that were
implemented
first. Sure, MPLS-VPN with 2547 is great, but it scales
horribly
and is difficult to
Here's some text from CCO regarding CEF and using source
and destination IPs to map a packet to one of a set of
load sharing links:
Configuring Per-Destination Load Balancing
Per-destination load balancing is enabled by default when you enable CEF. To
use per-destination load balancing, you do
I'm testing a setup using source specific multicast. On
the RPF interface for the target source IP (192.168.25.25)
I've configured the following command:
ip igmp static-group 232.232.232.232 source 192.168.25.25
This seems to get the right messages forwarded up towards
the source in order to
Heard there's a new requirement between the CCIE written and lab.
One now has to sing the following song on a street corner on
Tasman Drive. Passing score is 740.
http://puck.nether.net/~jared/gigflapping.mp3
Message Posted at:
Anyone have a pointer to a page which details what features
are in each feature set. For instance, what are feature
differences between the IP, IP Plus, and Service provider
feature sets?
Thanks
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7i=72236t=72236
Consider two routers which have 3 GEs between them (no L2
device between them).
Is it better to configure each of these GEs as
a standalone L3 connection or to combine them GEs into
an etherchannel (802.1ae?) bundle?
My $0.02 would be to keep them at L3 and not run another
protocol underneath
I'm not sure I understand completely why you want to do
this, and it's been a while since I've dinked with PBR,
but here's some thoughts on one might get this to work.
I've done something similar, but not exactly what's below,
so YMMV. Note, VRFs might fit better and I've listed some
details on a
)
-Original Message-
From: p b [mailto:[EMAIL PROTECTED]
Sent: Friday, June 27, 2003 2:45 PM
To: [EMAIL PROTECTED]
Subject: RE: policy based routing and backup [7:71482]
I'm not sure I understand completely why you want to do
this, and it's been a while since I've dinked with PBR,
but here's
Found this a bit unusual... have a feel for why it works
this way, but figured I'd float this to the list for
thoughts...
Got two routers connected via a serial interface.
R1 is assigned 192.168.2.1/30 on its serial
R2 is assigned 192.168.2.2/30 on its serial
On R1, do a debug ip icmp
And
Thanks. Yea, this is a real design.
Can't do the /25 statics to the entity that IGP advertises the
/24 as there are dual links and multiple hops and certain failure
scenarios will cause traffic to get blackholed.
Someone sent me a pointer off list (thanks Rob) that pointed
me to the bgp
Suppose I have a router which has a subnet x.x.x.0/24 defined
on some interface. Over one iBGP session I'd like to
advertise the x.x.x.0/24 subnet. Over another iBGP session,
I'd like to advertise x.x.x.0/25 and x.x.x.128/25. When
I config three network statements for these subnets in BGP,
Using BGP regexp, what's the show ip bgp regexp ...
command to show all routes which did not last come through
AS NNN? For example, if there are BGP routes with the following
AS_PATHs:
10 22 30
20 30
20 52 10 11
20 10
10
the command should return 10 22 30 and 10.
Thanks
PB
Isn't it standard practice for two entities, when setting up
a peering, transit, or partial transit relationship, to agree
on what routes will be sent over the links and then develop
route filters on each side accordingly? If this is done properly,
then a misconfiguration on one side should not
Don't have any gear to test this on, but what if you
put a network 1.1.1.1 mask 255.255.255.255 in your
AS 200--AS300 eBGP peer? The route received from AS100
will populate the routing table and thus cause AS200's
network statement to be satisfied and thus advertised.
This may make 1.1.1.1 to
Some question I had as I've been reading Doyle V2.
1) Question about next-hop-self. Suppose the router is
purely an iBGP router-- it does not have any eBGP
connections and is there is no redist into BGP. Does
setting this command on a iBGP neighbor have any affect?
If this router is a
I'm seeing what looks like inconsistent information being
reported by a route reflector client (192.168.100.14).
Below are two lines of output from debug ip bgp events and
debug ip bgp updates:
*Mar 3 09:06:26.265 UTC: BGP: 192.168.100.10 rcv UPDATE about
26.0.0.0/24 -- denied
*Mar 3
Priscilla Oppenheimer wrote:
p b wrote:
Actually using secondaries and DHCP should be a non issue with
any reasonable DHCP server platform. As you mention, in many
versions of IOS the interface's primary IP address is used
as the DHCP giaddr. If an interface has multiple secondaries
Argh. Tab and return doesn't work well in when posting through
the web page
Let me revise the last part of my message:
If the interface (or sub-interface) looks like:
int ethernet 4/0.42
ip address 10.0.1.1 255.255.255.0
ip address 10.0.2.1 255.255.255.0 sec
ip address 10.0.3.1
Oppenheimer wrote:
Thanks for all the info p b. It's very helpful.
Regarding the first situation, where the DHCP server is on
another segment and we're using a helper address to get the
requests over to the server:
We have established that if you use secondaries, the router
puts its
One of the cisco press books indicates one should use
type 1 externals when the route is being advertised by
1 ASBR and type 2 externals when there's a single
ASBR.
Are there any issues if one uses type 1 external even
when the route is being advertised by a single ASBR? It
would seem useful,
Comments inline:
Howard C. Berkowitz wrote:
At 5:00 PM + 12/3/02, p b wrote:
One of the cisco press books indicates one should use
type 1 externals when the route is being advertised by
1 ASBR and type 2 externals when there's a single
ASBR.
This is just plain wrong. The reason you
planning to use E1s in this situation but
wanted to float this out to the list to see if there might
be unexpected consequencies. From the feedback so far, there
doesn't seem to be.
Thanks
Peter van Oene wrote:
Some thoughts below
On Tue, 2002-12-03 at 13:26, p b wrote:
Comments inline
Actually using secondaries and DHCP should be a non issue with
any reasonable DHCP server platform. As you mention, in many
versions of IOS the interface's primary IP address is used
as the DHCP giaddr. If an interface has multiple secondaries,
one just needs to configure the DHCP server to be
Reading (yawn) RFC 2328 and there's mention of two uses of the
forwarding address in external LSAs (section 2.3). The
second use is where one makes an OSPF router a route server and
it generates external LSAs with the forwarding address in each
LSA set to the proper AS exit point IP. I guess
Thanks. I had expected that router bgp ABC and router bgp XYZ
did in fact start two processes. I hadn't tried applying a
second router bgp XYZ to a config to confirm this worked. But
as you point out, this isn't allowed (supported) and the router
reports the error:
router(config)#router bgp
as
described
above.
Again, not in your simple topology as far as I can tell.
Thanks for the thoughts so far. Be interested in more
feedback
on the above analysis.
Peter van Oene wrote:
On Sun, 2002-11-24 at 21:56, p b wrote:
Consider
-24 at 21:56, p b wrote:
Consider this a question around the theory behind why OSPF
did things a certain way. Somewhere along the way, Moy
et. al. decided that there was an issue with an ABR
processing
a summary LSA. Based on that, they decided to make a
design
decision
ABR2 instead of the
originating router's RID.
So, I (still) don't see an issue if the ABR behaved as described
above.
Thanks for the thoughts so far. Be interested in more feedback
on the above analysis.
Peter van Oene wrote:
On Sun, 2002-11-24 at 21:56, p b wrote:
Consider
Consider the following topology:
area_0---ABR_1area_1-ABR_2area_0
There are two area 0's. ABR_1 and ABR_2 will generate
type 3 summary LSAs for the respective area 0s and
flood the information into area_1. An internal
router in area 1 will see the summary LSAs from ABR_1
and
://www.ietf.org/internet-drafts/draft-ietf-ospf-abr-alt-05.txt)
Thanks
The Long and Winding Road wrote:
p b wrote in message
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
Consider the following topology:
area_0---ABR_1area_1-ABR_2area_0
There are two area 0'
:
p b wrote in message
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
Thanks. But this doesn't really answer my question. I
realize
that area 0 is partitioned. I'm not looking for an answer to
is there a rule that prevents this, but instead, what
breaks
if ABR_1 were to
Wondering if anyone has set their OSPF link costs based on
link distance instead of based on interface bandwidth. As
link speeds increase, corresponding serialization delay
decreases. So another possible value one might use for link
cost is the distance of the link instead of based on interface
I had posted earlier in the week regarding some questions about
iBGP, the routing table, and convergence. Have some more
information and some more detailed questions.
In terms of the design, the network consists of many routers
all running iBGP in a direct mesh or through route reflectors.
OSPF
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