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New Member

HSRP & BGP

We will be getting a circuit from the same ISP at two of our sites and will be doing eBGP.  Couple of notes. 1. We are fully aware of the risks associated with depending on a single ISP and have mitigated them as much as possible with the ISP. 2. We will be getting assistance on the eBGP setup from the ISP, so I’m not as concerned with that config at this point.

Site Summary

Site A:
Cisco 2900 Series (RtrA) connected to single Ethernet based ISP circuit (ISP-1-A)
eBGP will run between RtrA and ISP-1-A, default routes from provider only
Layer 2 Switch (SwA) connected to LAN of RtrA and uplinks to SwB

Site B:
Cisco 2900 Series (RtrB) connected to single Ethernet based ISP circuit (ISP-1-B)
eBGP will run between RtrB and ISP-1-B, default routes from provider only
Layer 2 Switch (SwB) connected to LAN of RtrB and uplinks to SwA

I need advise on the LAN side redundancy. Our goal is redundancy; load balancing is not a concern (If load balancing ever becomes a concern I will look at GLBP). We have several devices on the LAN side of the routers that can only use a single gateway. Given that I’ve surmised I need to use HSRP in some way for LAN gateway redundancy.

After doing some research I’ve come up with the following solutions. Can you please give me recommendations/suggestions…tell me if I’m way off base? Thanks!

1. HSRP with Object Tracking, No IGP.
HSRP handles LAN gateway failover if a router dies. Object tracking ensures LAN gateway failover if an interface fails or if an interface is up, but there is an upstream traffic issue. ie. track the physical WAN interface and use an IP SLA icmp to track a specific upstream IP incase of an upstream traffic issue.

2. HSRP with OSPF
HSRP handles LAN gateway failover if a router dies. OSPF redistributes eBGP default routes to RtrA and RtrB so that each router should have a route to the ISP even if they loose their local ISP circuit.  i.e if ISP-1-A on Router A goes down, Router A knows to send traffic out ISP-1-B via RtrB. In other words, traffic enters RtrA LAN, but exits on RtrB WAN.

3. HSRP with iBGP
HSRP handles LAN gateway failover if a router dies. I have no experience with BGP, but assuming this would work similar to the OSPF solution above except for the required iBGP config and possible route reflectors?

2 REPLIES
New Member

HSRP & BGP

Hi,

In my opinion,

option 1 :

Simple and reliable, but no load balance for outgoing traffic (i.e traffic will use ISP 1 only when it down, it will use ISP 2)

option 2:

If the eBGP routes you get is 0.0.0.0 (default) then redistribute to ospf will have 2 entry on the routing table, so there is load balance.

option 3:

I don't think need to add another burden to the router to run iBGP, which will only achive what option 1 achieve ( no load balance, since router will prefer eBGP routes over iBGP)

HTH,

Vikram

Re: HSRP & BGP

Hi

I would say option 1 is the simplest one to go with

And the other option you might use is the last one where you have ibgp between the routers and ebgp to the ISP and hsrp to the LAN

Keep it simple always

HTT

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