11-01-2017 02:54 PM - edited 03-05-2019 09:25 AM
I've inherited a network with my new job. The routing is working but I'll describe the topology and then ask my question...
I have two different ISP WAN circuits. (Thus two different AS numbers)
I have two core routers connected to the respective ISPs and each router has a different AS number. (I see most designs having both routers in a single AS)
BGP from first router is peered with its respective ISP AS number and with the other Core Router AS
BGP from second router is peered with its respective ISP AS number and with the other Core Router AS
Show IP BGP route shows routes and none of them appear to be iBGP.
Is the fact that both core routers have different AS numbers causing everything to be eBGP?
Solved! Go to Solution.
11-02-2017 03:58 PM
11-01-2017 03:19 PM
Hello
The design you have describe isn't uncommon.
Do the two site routers have the same bgp ASN number ?
They could be interconnected via an IGP such as ospf /eigrp or even rip instead of ibgp, Anyhow....Whats your question?
res
Paul
11-01-2017 05:37 PM
Can I just verify that your ASN is the same for both routers, one belonging to your company, but the two routers each peer with unique ISP ASNs?
11-01-2017 07:52 PM
Hi Paul. Both of my on site routers each have different BGP AS numbers. I just wanted to verify that this design is not out of order with what should be done. I can also confirm that there is an OSPF area that includes my two routers.
The main reason for this inquiry was to verify that I am running eBGP and not iBGP. My company is looking to implement some new SD-WAN devices that are not able to pass iBGP routes but will work fine with eBGP.
11-02-2017 02:52 PM
The fact that your on site routers and core routers have different AS numbers is indeed the reason why your routes show up as EBGP and not IBGP. Your implementation is not a common one. But I would not say that it was out of order.
I do not know enough about your environment to say anything meaningful about the changes that you are planning for SD-WAN. If these new devices will not pass IBGP then it means that they do not want to be placed between routers running BGP for the enterprise to two external peers. And that is just what you are about to do. I would approach this with caution.
HTH
Rick
11-02-2017 03:58 PM
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