Let's get into the nitty gritty of things... I am going to start backwards....
1) you should have IP Address on loopback interfaces on each of the routers. 2) you should have an igrp protocol running between all of these routers so that they can reach each other's Loopback Address (OSPF is best) 3) your three routers should be running iBGP mesh between each other, i.e. two ibgp sessions on each router, each of those sessions to the other two (a.k.a. route reflector settings, in regards to the bgp instance, where the update source is the loopback ip ). so now you should have a bgp table on each of the three routers, and they should be able to see all the different routes which are reachable via the other router.. 4) once you have all of the above setup, then you can do traffic engineering... keep in mind, in-bound traffic engineering is done via, bgp communities, asn prepends, etc out-bound traffic innerspring is done via local pref settings. hint... not sure who are your ISP's but in some cases, you can use bgp communities for their upstream (as long as they do not filter or overwrite the communities) to have the desired affect. Regards. Faisal Imtiaz Snappy Internet & Telecom 7266 SW 48 Street Miami, FL 33155 Tel: 305 663 5518 x 232 Help-desk: (305)663-5518 Option 2 or Email: supp...@snappytelecom.net > From: "Nick Bright via Mikrotik-users" <mikrotik-users@wispa.org> > To: mikrotik-users@wispa.org > Sent: Monday, April 10, 2017 11:51:39 AM > Subject: [Mikrotik Users] Multi-hop BGP > 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 > Mikrotik-users@wispa.org > http://lists.wispa.org/mailman/listinfo/mikrotik-users
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