Lan2Lan with 2 ASR

[matou801]

Hello,

Currently I have an ASR1001-X which acts as a collection router for Internet subscribers and a BGP router with a full view for IP transit, we have an ASN and a prefix. Everything is in the same POP. (Ex: My prefix 50.50.50.0/24)

My configuration
0/0/0 Transit IP ISP1 5.5.5.5/30 <- IP ISP1
0/0/1 Transit IP ISP2 6.6.6.6/30 <- IP ISP2
0/0/2 Collect with the vlans that the infrastructure operator delivers to me.
0/0/2.1500 Tenant1 50.50.50.50/30 <- IP my prefix
0/0/2.1501 Tenant2, 50.50.50.55/30 etc ....
and the BGP config with the two ISPs which announce my prefix.

We change the POP for IP transit, DNS server hosting and storage, only collection remains and a Lan2lan has been installed between the two POPs.
I have an ASR1001-x on the new POP, which will do the job for the new full view transit,
0/0/0 NEW ISP Transit IP 7.7.7.7/30
0/0/1 NEW ISP Transit IP 8.8.8.8/30
I'm going to disable the BGP config on the old ASR, which will just serve as a collection router. I will install two switches on each side of the LAN2LAN to pass the traffic.

My question is
How to send all the traffic on the new ASR (Collection router> Lan2Lan> IP transit router (bgp config). How to pass the 0/0/2 card to the new ASR? I do not have an IP on the 0/0/2 These are only subinterfaces with an encapsulation number that the collection operator gives me.

Can a simple static-route work ?

Thank you

[Giuseppe Larosa]

Hello @matou801 ,

what do you mean with LAN2LAN ?

you say you are going to deploy two switches . Can we assume that you are referring to a point to point L2 transport service provided like an EoMPLS pseudowire?

Generally LAN to LAN is used in the context of IPSec VPN but if you deploy switches they are likely not able to support IPSec based VPNs.

if you have a L2 transport service you can configure a routing protocol between the two ASRs like OSPF just to

inejct a default route from NEW ASR

sends routes that are in your prefix from OLD ASR

>> How to pass the 0/0/2 card to the new ASR? 

as explained above with the old router advertising the subnets of each VLAN based subif

Hope to help

Giuseppe

[matou801]

Hello Giuseppe, 

The Lan2Lan is a L2 (transport Level2) who is transparent to dynamic routing protocols. 

So, I think I can do OSPF.
Do you need level 3 switches at each end to communicate the two ASRs, or level 2 switches are sufficient?

Thank you.

[Giuseppe Larosa · Accepted solution]

Hello @matou801 ,

>> Do you need level 3 switches at each end to communicate the two ASRs, or level 2 switches are sufficient?

L2 switches are enough, they just need to use the same VLAN towards the local ASR and toward the L2 transport service.

I mean two access ports in the same VLAN is all what is needed on each L2 switch.

OSPF will run between the two ASR routers.

Hope to help

Giuseppe