What you are seeing with the loss of the bgp route is due to iBGP standard behavior. To avoid route loops only local routes are sent to ibgp peers.
Thus iBGP does require either a full mesh of all peers each other or the use of route reflectors to distribute the full routing table to all sites if that is needed.
Your topology would probably be a typical route reflector on router 2 & 3 with each other site 4,5,6 remote and 1 core peering to both route reflectors for redundancy.
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Steve Puluka BSEET - Juniper Ambassador
IP Architect - DQE Communications Pittsburgh, PA (Metro Ethernet & ISP - Retired)
http://puluka.com/home------------------------------
Original Message:
Sent: 10-30-2022 07:58
From: Anonymous User
Subject: Routing Loop
This message was posted by a user wishing to remain anonymous
Updated the diagram , in terms of routing table
on R1 -
BGP Route present for 2.2.2.2/32 next hop Router 2 (before the cutover)
BGP Route present for 2.2.2.2/32 next hop Router 2 +Router 3 (After the cutover,ECMP due to equal cost)
R2
BGP Route present for 2.2.2.2/32 next hop Router 5 (before the cutover)
BGP Route NOT present for 2.2.2.2 (After the cutover)
the trace route from R1
1.1.1.1 -->R1-->R2---(Following bigger subnet 2.0.0.0/24)
---->R1---(OSPF Cost equal between R2 and R3)---> R2 -->R1(loop)
Original Message:
Sent: 10-30-2022 06:52
From: Anonymous User
Subject: Routing Loop
This message was posted by a user wishing to remain anonymous
Hi Community
need some help with a issue we faced in the network , we deleted IBGP and OSPF between Router 2 to to Router 5 , after which router 2 didnt had router present for 2.2.2.2. and we started to have traffic from Router 1 (source 1.1.1.1) ECMP'ed toward 2.2.2.2 , next hop Router 2 and Router 3 as OSPF costs matched , which cause intermittent outage.
As when the packets reached router 2 , there was no route present for 2.2.2.2 and traffic started to loop between router 1 and router 2. While the packets which were sent via Router 3 were fine.
Is there any way we can over come this issue, any feature which could help in this , dont want to add static routes