AW: Conditionally Advertising BGP Routes in a VRF?

From: Roger RPF (rpf@bluemail.ch)
Date: Wed Jun 25 2008 - 07:04:12 ART


Hi,

Maybe I'm too tired to get the point but to me that's not the same (please
correct me if I'm wrong). With conditionally advertiseing I have the
exist-maps or non-exist maps which check if a prefix exist in that routing
table or not, and based on that fact, I'll forward a prefix to a neighbor or
not.
With route-maps, distribute-lists or filter-list I can only filter based on
some facts but not conditionally.
Am I wrong with that??
So far, I could not find a solution to do that within a VRF...

Here the description of the DocCD:

Conditionally Advertising BGP Routes

Perform this task to conditionally advertise selected BGP routes. The routes
or prefixes that will be conditionally advertised are defined in two route
maps, an advertise map and an exist map or nonexist map. The route map
associated with the exist map or nonexist map specifies the prefix that the
BGP speaker will track. The route map associated with the advertise map
specifies the prefix that will be advertised to the specified neighbor when
the condition is met. When an exist map is configured, the condition is met
when the prefix exists in both the advertise map and the exist map. When a
nonexist map is configured, the condition is met when the prefix exists in
the advertise map but does not exist in the nonexist map. If the condition
is not met, the route is withdrawn and conditional advertisement does not
occur. All routes that may be dynamically advertised or not advertised need
to exist in the BGP routing table for conditional advertisement to occur.
These routes are referenced from an access list or an IP prefix list.

Von: Shaughn Smith [mailto:Shaughn.Smith@za.verizonbusiness.com]
Gesendet: Mittwoch, 25. Juni 2008 09:54
An: Roger RPF; ccielab@groupstudy.com
Betreff: RE: Conditionally Advertising BGP Routes in a VRF?

Hi

Like I said yesterday. You can use route-maps, distribute-lists and filter
lists in your VRF configuration.

Below confirms it

xxxxx(config-router)#address-family ipv4 vrf xxxxxxx
xxxxxx(config-router-af)#neighbor 192.168.1.1 ?
  activate Enable the Address Family for this Neighbor
  advertisement-interval Minimum interval between sending BGP routing
updates
  allowas-in Accept as-path with my AS present in it
  as-override Override matching AS-number while sending update
  capability Advertise capability to the peer
  default-originate Originate default route to this neighbor
  description Neighbor specific description
  disable-connected-check One-hop away EBGP peer using loopback address
  distribute-list Filter updates to/from this neighbor
  dmzlink-bw Propagate the DMZ link bandwidth
  ebgp-multihop Allow EBGP neighbors not on directly connected
networks
  filter-list Establish BGP filters
  inherit Inherit a template
  local-as Specify a local-as number
  maximum-prefix Maximum number of prefixes accepted from this
peer
  next-hop-self Disable the next hop calculation for this
neighbor
  next-hop-unchanged Propagate the iBGP paths's next hop unchanged for
this neighbor
  password Set a password
  peer-group Member of the peer-group
  prefix-list Filter updates to/from this neighbor
  remote-as Specify a BGP neighbor
  remove-private-as Remove private AS number from outbound updates
  route-map Apply route map to neighbor
  route-reflector-client Configure a neighbor as Route Reflector client
  send-community Send Community attribute to this neighbor
  send-label Send NLRI + MPLS Label to this peer
  shutdown Administratively shut down this neighbor
  soft-reconfiguration Per neighbor soft reconfiguration
  timers BGP per neighbor timers
  translate-update Translate Update to MBGP format
  ttl-security BGP ttl security check
  unsuppress-map Route-map to selectively unsuppress suppressed
routes
  update-source Source of routing updates
  version Set the BGP version to match a neighbor
  weight Set default weight for routes from this neighbor

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Roger RPF
Sent: Wednesday, June 25, 2008 7:46 AM
To: ccielab@groupstudy.com
Subject: WG: Conditionally Advertising BGP Routes in a VRF?

Hi Group,

Need to ask again...is there no possibility in a VRF for conditionally
advertising?

-----Urspr|ngliche Nachricht-----
Von: nobody@groupstudy.com [mailto:nobody@groupstudy.com] Im Auftrag von
Roger RPF
Gesendet: Dienstag, 24. Juni 2008 15:29
An: ccielab@groupstudy.com
Betreff: Conditionally Advertising BGP Routes in a VRF?

Hi Group,

Is it possible to do conditionally bgp route advertising in a vrf? I cannot
configure it and I cannot really find information about it. The normal
config is as the following:

http://www.cisco.com/en/US/docs/ios/iproute/configuration/guide/irp_bgp_basi
c_net_ps6350_TSD_Products_Configuration_Guide_Chapter.html#wp1055661

But how to do that within a VRF?? Any ideas??

regards

Roger



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