Greetings,
I'm working on a bit of BGP configuration that I'm having trouble making
work as I'd like.
There are three routers involved:
1. RouterA - connected to Primary Tier 1 ISP, does BGP with ISP-A.
1. I share this router with another WISP (we split the connection),
so this router does BGP with ISP-A, the other WISP, and my edge
router
2. RouterB - does BGP with RouterA, and connects to my network.
3. RouterC - does BGP with Secondary Tier 2 ISP (backup path), does BGP
with ISP-B
1. Connects to the network the same way Router B does, and is
connected to RouterB in the same switched network in the same
subnet e.g. they are directly adjacent in the topology.
All three routers have the same ASN (mine).
My desired configuration is that ISP-A is the preferred ISP for all
traffic, unless ISP-A is unavailable (the most likely scenario being the
11GHz backhaul between RouterA and RouterB going down), in that case
RouterC should function as the gateway to ISP-B.
Some issues to overcome in configuring this are:
* ISP-B doesn't provide any BGP Communities for which to set "Backup
route" preference
* Path Prepending doesn't work, because ISP-B is better connected to
numerous sources of significant traffic; and even prepending as many
as 16 hops, is still preferred. If prepending was going to work,
that many should do it.
When I peer RouterB and RouterC, RouterA either doesn't receive the
routes from Router C; or receives them, but the Next Hop is Router C's
IP address; which Router A invalidates the route, because it's not
directly attached.
I'm sure that I'm just doing something incorrectly, but I haven't been
able to identify what. Any suggestions?
--
-----------------------------------------------
- Nick Bright -
- Vice President of Technology -
- Valnet -=- We Connect You -=- -
- Tel 888-332-1616 x 315 / Fax 620-331-0789 -
- Web http://www.valnet.net/ -
-----------------------------------------------
- Are your files safe? -
- Valnet Vault - Secure Cloud Backup -
- More information & 30 day free trial at -
- http://www.valnet.net/services/valnet-vault -
-----------------------------------------------
This email message and any attachments are intended solely for the use of the
addressees hereof. This message and any attachments may contain information
that is confidential, privileged and exempt from disclosure under applicable
law. If you are not the intended recipient of this message, you are prohibited
from reading, disclosing, reproducing, distributing, disseminating or otherwise
using this transmission. If you have received this message in error, please
promptly notify the sender by reply E-mail and immediately delete this message
from your system.
_______________________________________________
Mikrotik-users mailing list
[email protected]
http://lists.wispa.org/mailman/listinfo/mikrotik-users
