[c-nsp] Route reflectors, BGP router redundancy et. Al.

[Joe Maimon]

Dracul wrote:
> Hi All,
> 
> I'm building a design that involves having a 2nd BGP router to act as a
> backup if something goes wrong with the main router (heaven forbid). I have
> two peers to different ISP's. There are some questions I have in mind:
> 
> a. Should my configuration involve route reflectors?
> b. Do I need interconnectivity between the 2 routers? ethernet or serial?
> c. Where would the two ISP links attach? Router A or B?
> 
> Thanks for your time!
> Chris

Here is a nice and simple design.

Suppose you have two 7206-NPE-G1 and two 2950 with two gig ports.

Each 2950 has gig connection to other 2950 and to one NPE-G1.

The npe-g1 connection is a dot1q trunk.

Suppose each ISP is 100mb feed.

Connect each one to one of the 2950.

Request your ISPs use a /29 or larger or multiple /30 or multiple vlans 
on the peering link.

Use a vlan for each ISP and a vlan for internal routing and a vlan for 
local lan clients, or anything else.

VLAN 1 - Unused
VLAN 2 - ISP A
VLAN 3 - ISP B
VLAN 4 - IBGP
VLAN 5 - Local servers
VLAN 6 - etc...

You can either use the pb&j approach for igp such as ospf for the 
internal routing edges and ibgp over loopbacks (if you want to design 
something correct and expandable) or simply ibgp peer between the 
routers on the vlan 4 subinterface (if you dont).

Have each ISP peer with each router.

Each router will have 3 BGP sessions at minimum.

Use HSRP/VRRP on the VLAN 5 and etc vlans.