MPLS using ripv2 bridge

[zeuscyril]

hi all,

here my scanerio,

rightnow we are using the wireless bridge between the sites , so the network is same on both ends all the servers and ip telephony in one site.(SITE A)

now we are got from ISP layer 3 MPLS link using ripv2 routing.

is it possible to make the MPLS link also like wireless brige?

or

the networks on both ends should be different. if it is , how to route all the traffic through the MPLS to other side .( like internet and VOICE).

here the network details

172.16.0.0/16 -- my site A network which all devices are there

my MPLS IP -site A 172.16.1.61/30

connected with cisco router one interface as 172.16.1.55/16 and MPLS interface as 172.16.1.62/30

and Site B -- 172.16.1.57/30

connected with cisco router one interface as 172.16.1.56/16 and MPLS interface 172.16.1.58/30

this what i have done it but not tested.( i am sure this is not correct)

will this work or we need to have seperate networks on both end?

thanks

cyril

[Giuseppe Larosa]

Hello Cyril,

from your post I understand that you have bought an MPLS L3 VPN service with PE-CE protocol RIPv2.

the setup that you would like to implement cannot work because the router would complain of overlapping IP subnets in different LAN interfaces.

Even if this would be supported the routing would not work with same major network 172.16/16 at the two sites.

Site B can use subnets taken from 172.16.0.0/16 because RIPv2 is classless (it carries the subnet mask in routing updates).

You need to redesign and deploy an appropriate address plan, you cannot use a flat network anymore.

For example, you can use subnets /24 taken from 172.16.0.0/17 at Site A and subnets /24 from 172..16.128.0/17 at Site B.

Or to avoid to make changes at site A you can use a different major network at site B, like 172.17.0.0/16.

In short the service cannot act as a bridge, there are L2 VPN service like EoMPLS that could do that, but not the service you have bought.

Edit:

routing would need configuration of router rip process on your CE routers and they  need to build RIP neighborship with the local SP PE node. Propagation of routes is performed by MPLS SP in MP BGP and it is transparent to you.

Hope to help

Giuseppe

[zeuscyril]

hi Giuseppe,

thanks for your reply,

suppose if i have different subnets on the both end then how i can route all the traffic to one end.

becuase the internet is on one end. so the default route should pass through the MPLS.

can you provide some example through RIPv2

there is some command "defualt-orignate" will do the following task?

thanks

cyril

[Giuseppe Larosa]

Hello Cyril,

yes the default-originate command is present for RIP  see

http://www.cisco.com/en/US/docs/ios-xml/ios/iproute_rip/command/irr-cr-rip.html#GUID-B7C024D6-3A1F-46B1-8B6A-D31AD7A7D5B0

So the CE with internet access will have to send out a default route

Hope to help

Giuseppe

[zeuscyril]

Hi G

In Site-B I have 2 different subnets. In that I need to route 2 different default originate for 2 differenet gateways in Site-A

because in my site b Router i had has 3 interfaces so i am creaing 2 different subnets in that.

For example:

Site-B : 2 Subnets

1. 192.168.1.0/24     -> default orginate route 172.16.1.1 (Site-A's Router A's IP address)

1. 192.168.2.0/24     -> default orginate route     10.1.1.1  (Site-A's Router B's IP address)

Site-A : 2 Routers

1. Router A  :  172.16.1.1

2. Router B  :   10.1.1.1

Will it be possible ?  Please assist me on this

[Giuseppe Larosa]

Hello Cyril,

my understanding is that you have bought a single L3 VPN service with an access link in site A and one link in site B.

The SP network is in the middle and does not allow to achieve your objective, because it makes a choice of single best route, and it propagates only this.

Inside Site A, PBR policy based routing based on source address can be used on CE device (the router connected to the MPLS cloud) to send traffic to RA or RB depending on the source address of traffic originated at SiteB

example:

I make the assumption that you have a third router at site A RC that acts as CE node of site A.

I also assume a common LAN between RA,RB and RC inside siteA.

The following are on this CE node.

access-list 111 deny ip 192.168.1.0 0.0.0.255 172.16.0.0 0.0.255.255

access-list 111 deny ip 192.168.1.0 0.0.0.255 10.1.1.0 0.0.0.255.

access-list 111 permit ip 192.168.1.0 0.0.0.255 any

access-list 112 deny ip 192.168.2.0 0.0.0.255 172.16.0.0 0.0.255.255

access-list 112 deny ip 192.168.2.0 0.0.0.255 10.1.1.0 0.0.0.255.

access-list 112 permit ip 192.168.2.0 0.0.0.255 any

route-map PBR-siteB permit 10

match ip address 111

set ip next-hop

route-map PBR-siteB permit 20

match ip address 112

set ip next-hop

interfaces fas0/0

desc to SP MPLS network

ip policy route-map PBR-siteB

+

RIP configuration towards SP

the first two lines of ACL 111 are for allowing inter site routing, only traffic with a destination outside siteA have to be processed by PBR.

warning: this is just an example to show the logic of PBR .and I haven't checked all the commands

PBR works inbound on traffic received on CE router on the MPLS L3 VPN access link

Edit:

RA and RB will also need a NAT configuration.

Hope to help

Giuseppe