BGP over gre tunnel or EOIP Keeps flapping

RouterOS Forwarding Protocols
1

Hi all,

Not well versed in these protocols. Im trying to establish bgp over internet to another router that requires the first routers tables. I setup EOIP tunnels and bgp gets a connection and forwards the routes to the other router but the tunnel then starts flapping every second.. If I disbale bgp, the tunel stays up no problem. Same happens with a GRE tunnel. Im assuming im creating some sort of loop? The tunnel IPs are a unique private /30 between them. Tried also MTU 1500. Thoughts?

Regards,

2

bump

3

You forgot your network drawing and configuration export!

4

check the remote address of the tunnel.
Usually i’m living the tracert running and waching at loss and the path

5

A common problem is that start of BGP inserts other routes in the routing table and this overrides the route towards the BGP peer, causing loss of the peer connection.
But we never know until we know his network layout and configuration…
(having EoIP usually indicates a not very proficient admin, and so does writing “bump” in a reply to one’s own posting)

6

Here is the worlds best network diagram..

Locations are connected to transit and local IX. I wish to share the learned routes from local IX with my private IX. At the moment,

I am able to share the local IX routes learned in upstream router with core router. I wish to share the learned local IX routes in upstream router with another identical location and vice versa.

I had previously setup OSPF and MPLS among all participating routers and LSA etc all mapping was shared but as Im not proficient at all in those routing protocols and went with BGP as I can see the routes populate.

image upload not working it seems

Transit1 Transit 2 Local IX
bgp
Upstream Router
bgp
Core Router-Local IX
direct attach
Switches

gre or eoip
internet
gre or eoip


Transit1 Transit 2 Local IX
bgp
Upstream Router
bgp
Core Router-Local IX
direct attach
Switches

7

hello.

I setup EOIP tunnels and bgp gets a connection and forwards the routes to the other router but the tunnel then starts flapping every second.. If I disbale bgp, the tunel stays up no problem. Same happens with a GRE tunnel. Im assuming im creating some sort of loop? The tunnel IPs are a unique private /30 between them. Tried also MTU 1500. Thoughts?

  1. what did the bgp router log say about those flapping?

  2. looped? could be. but later on. let see your network layout.

  3. how many tunnel did you build for each back to back router? did you do bonding on those tunnel as well?

8

Only one side of the GRE or EOIP tunnel flaps but add’s nothing to the logs, nor are there any BGP logs entries when this happens. I only see on the router receiving the new tables from BGP stop adding routes momentarily and then adds, then stops as the flapping continues…

9

hello mickey,

ok.

  1. what does the eoip or gre interface log say about those flapping? and which method did you put those tunnels? inside a bridge?

  2. what hardware platform did you run that bgp routing? have you checked its ram?

  3. the simplest thing in filters: never accept own routes sent back from any peers.

ok. good luck :+1:t2:

10

tunnels are not bridged

upstream router is 4Gb ram and core router is 16Gb ram

Can you provide an example rule for v7 to never accept own routes back from peers? Would be much appreciated.