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BGP or EIGRP?

louis0001
Level 3
Level 3

We have 50 remote sites that are connected via an ISP provided MPLS network using BGP for routing (no internet breakout)

These remote sites connect to our 2 main sites (Site A & Site B) which provide the internet breakout.

The two main sites are also connected to each other via a PtP 1gb link. We use EIGRP for routing between these and we also redistribute the BGP routes into EIGRP to make the routing simple.

I'd like to tidy this up and remove the EIGRP and replace with BGP rather than redistribute the the routes from BGP to EIGRP.

Should I do this or is it advisable to keep EIGRP at the core?

6 Replies 6

luis_cordova
VIP Alumni
VIP Alumni

Hi @louis0001 ,

 

Check this discussion of the community to a similar doubt.

I hope it's useful for you.

https://community.cisco.com/t5/other-network-architecture/ibgp-vs-igp-ospf-or-rip/td-p/613098

 

Regards

To be honest, it's a fairly simple network and I was just looking a tidying the core routing up and making it more understandable by keeping the routing protocols down to minimal ie Just use BGP and static routing ie remove EIGRP & OSPF

What I'm trying to achieve is what we already have in that if we create a network at the remote sites, it's automatically advertised at the core sites without user intervention.

Also to re-route should the SITE A or SITE B lose it's connectivity to the MPLS eg

Remote SITES (bgp) > SITE A -- (eigrp) -- SITE B < Remote SITES (bgp)

 

Change to:

Remote SITES (bgp) > SITE A -- (bgp) -- SITE B < Remote SITES (bgp)

 

It's really up to you and what you feel most comfortable with. 

 

At one of the places I worked we had a similar setup eg. EIGRP internally, BGP for MPLS and then redistribute BGP into EIGRP (no internet). 

 

We did not redistribute EIGRP into BGP but took advantage of summary routing eg. each site advertised a summary for it's internal subnets and we deliberately left room for future growth so we could easily add subnets without having to update the BGP configuration at all. 

 

Jon

Hello,

 

on a side noet, how many routers do you have at each site ? If it is only one router, you can get rid of EIGRP, if not, keep in mind that BGP requires a full mesh, or route reflectors...

Hi,

at the remote sites there is one router running BGP.

At the core sites, there are 2 routers on each site - one connecting the site to the ISP provided MPLS network above (running BGP) and another router connecting the core site to the other core site via a PtP link. The latter is the part of the network that uses EIGRP only ie SITE A to SITE B and vice versa. The remote sites are advertised into this.

 

I was thinking something like:

At Core SITE A:

R1:

router bgp 65000
network 10.0.0.0 mask 255.255.255.0
neighbour 10.180.20.1 remote-as 16000 <<< ISP AS number
neighbour 10.0.0.2 remote-as 65001 <<< R2

 

R2:

router bgp 65001
network 10.0.0.0 mask 255.255.255.0
network 192.168.100.0 mask 255.255.255.252  <<< SITE B PtP
neighbour 10.0.0.1 remote-as 65000 <<< R1
neighbour 192.168.100.2 remote-as 65004 <<< R4

 

At Core SITE B:

R3:

router bgp 65003
network 10.0.1.0 mask 255.255.255.0
neighbour 10.180.20.20 remote-as 16000 <<< ISP AS number
neighbour 10.0.1.2 remote-as 65004 <<< R4

 

R4:

router bgp 65004
network 10.0.1.0 mask 255.255.255.0
network 192.168.100.0 mask 255.255.255.252  <<< SITE A PtP
neighbour 10.0.1.1 remote-as 65003 <<< R3
neighbour 192.168.100.1 remote-as 65001 <<< R2

 

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