From: David C Prall (dcp@xxxxxxxxxxx)
Date: Fri Jan 05 2001 - 18:41:49 GMT-3
I believe this is confusion between internal and external routes. Internal
BGP routers must be fully meshed, they only advertise their local networks
to other internal neighbors. External BGP routes will be advertised to other
internal neighbors. The use of a route reflector allows internal routes to
be advertised to other internal routers, thus relieving the need for a fully
meshed topology.
David C Prall dcp@dcptech.com http://dcp.dcptech.com
----- Original Message -----
From: "Connary, Julie Ann" <jconnary@cisco.com>
To: <ccielab@groupstudy.com>
Sent: Friday, January 05, 2001 4:23 PM
Subject: route-reflector question
> Hi All,
>
> I have a frame-relay hub and spoke network with the hub as the
> route-reflector server and the spokes as clients.
>
>
> R3---------------EBGP ---------R4
> | 137.20.34.3 137.20.34.4
> | 137.20.1.3
> |
> IBGP
> |
> |
> | 137.20.1.1 137.20.1.5 137.20..129.5 137.20.129.7
> R1-----------------ibgp ---------R5----------EBGP ------------R7
>
>
> R1 is the frame-relay hub with R3 and R5 as spokes.
> R7 is initiating a route - 160.0.0.0/4. R4 is also intiating a route -
> 172.168.2.0
> I had setup R1 to route-reflect to R5, but not to R3. So I had expected
> that R5 would see the
> route from R4, but R3 should not see the route from R7 - as R1 should not
> reflect it - correct?
>
> On R3 I see the following:
>
> r3#show ip bgp
> BGP table version is 33, local router ID is 137.20.31.65
> Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal
> Origin codes: i - IGP, e - EGP, ? - incomplete
>
> Network Next Hop Metric LocPrf Weight Path
> *>i160.0.0.0/4 137.20.129.7 100 0 3 i
> *> 172.168.2.0/24 137.20.34.4 0 0 1 ?
>
> r3#show ip bgp 160.0.0.0
> BGP routing table entry for 160.0.0.0/4, version 33
> Paths: (1 available, best #1)
> 3, (aggregated by 3 170.10.10.1)
> 137.20.129.7 (metric 84) from 137.20.1.1 (137.20.129.5)
> Origin IGP, localpref 100, valid, internal, atomic-aggregate, best
> Originator : 137.20.129.5, Cluster list: 137.20.11.33
>
> With a BGP setup of:
>
> !
> router bgp 2
> neighbor 137.20.1.1 remote-as 2
> neighbor 137.20.34.4 remote-as 1
>
>
> On R1 I see:
>
> r1#show ip bgp
> BGP table version is 25, local router ID is 137.20.11.33
> Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal
> Origin codes: i - IGP, e - EGP, ? - incomplete
>
> Network Next Hop Metric LocPrf Weight Path
> *>i160.0.0.0/4 137.20.129.7 100 0 3 i
> *>i172.168.2.0/24 137.20.34.4 0 100 0 1 ?
>
> r1#show ip bgp 160.0.0.0
> BGP routing table entry for 160.0.0.0/4, version 25
> Paths: (1 available, best #1, advertised over IBGP)
> 3, (aggregated by 3 170.10.10.1), (Received from a RR-client)
> 137.20.129.7 (metric 84) from 137.20.1.5 (137.20.129.5)
> Origin IGP, localpref 100, valid, internal, atomic-aggregate, best
>
> with a bgp setup of:
>
> router bgp 2
> no synchronization
> neighbor 137.20.1.3 remote-as 2
> neighbor 137.20.1.5 remote-as 2
> neighbor 137.20.1.5 route-reflector-client
> neighbor 137.20.12.2 remote-as 2
> neighbor 137.20.12.2 route-reflector-client
>
> (note that 137.20.1.3 is not a route-reflector-client.)
>
> On R5 I have:
>
> r5#show ip bgp
> BGP table version is 3, local router ID is 137.20.129.5
> Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal
> Origin codes: i - IGP, e - EGP, ? - incomplete
>
> Network Next Hop Metric LocPrf Weight Path
> *> 160.0.0.0/4 137.20.129.7 0 3 i
> *>i172.168.2.0/24 137.20.34.4 0 100 0 1 ?
> r5#show ip bgp 160.0.0.0
> BGP routing table entry for 160.0.0.0/4, version 3
> Paths: (1 available, best #1, advertised over IBGP)
> 3, (aggregated by 3 170.10.10.1)
> 137.20.129.7 from 137.20.129.7 (170.10.10.1)
> Origin IGP, valid, external, atomic-aggregate, best
>
> with a setup of:
>
> router bgp 2
> no synchronization
> neighbor 137.20.1.1 remote-as 2
> neighbor 137.20.129.7 remote-as 3
> !
>
>
>
> any ideas why R3 sees this route? Is this correct?
>
> thanks,
>
> Julie Ann
>
>
> ------------------------------------------------------------------------
> Julie Ann Connary
> | | Network Consulting Engineer
> ||| ||| Federal Support Program
> .|||||. .|||||. 13635 Dulles Technology Drive,
> Herndon VA 20171
> .:|||||||||:.:|||||||||:. Pager: 1-888-642-0551
> c i s c o S y s t e m s Email: jconnary@cisco.com
>
> ------------------------------------------------------------------------
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