Moving from L2 network to L3.

Question

Hi guys,
Recently i have start working to a small Service Provider and we are delivering ethernet leased lines to the end customer.
Our network is consisted of many ME 3600X and one 7609-S. The interconnections for all these are made by microwave point to point links (relay points) and for customer ethernet service we are using point to multipoint links (base stations) . In the attachement you can see the network topology.
The network is configured as a Layer 2 which meens that all point to point links are configured as Trunks with service intances.
There are no redundant links and Spanning Tree is not currently in use.
To add a customer we are creating a new vlan on ME 3600X and we are assigning that vlan to an access port, the vlan is added to whole path of ME switches and in the 7609-S we are creating service instance, vlan and interface vlan.
Sample Configuration
Ending ME 3600X
vlan 503
name TEST
interface giga0/5
description TEST
switchport access vlan 503
Middle  ME 3600X
vlan 503
name TEST
7609-S
bridge-domain 503
vlan 503
name TEST
interface giga 0/5
service instance 503 ethernet
encapsulation dot1q 503
rewrite ingress tag pop1 symmetric
brigde-domain 503 split-horizon
interface Vlan503
description TEST
ip address xxx.xxx.xxx.xxx 255.255.255.252
no ip redirects
no ip unreachables
We are in progress of buying a second Cisco 7609-S for redundancy and some ME 3600X for network expansion and probably there will be redundant point to point links. To make our netwotk more effiecient and scalable we would like to move on from L2 to L3.
One question is to setup SVIs on MEs and add them to the routing process or is more preferable to use pure L3 ports to point to point links?
Second question is regarding which protocol to use ISIS or OSPF?
In case of enabling a routing process is there any resone to use MC-LAG to 7609s ?
And last one. Is there something to watch out, so that customers don't exerience service interruption?
Thank you in advance.

Answer 1

You could have point-to-point L3 links between ME3600 and 7600 (with OSPF or ISIS).
And On ME3600 you could have this config :
vlan 503
name TEST
interface giga0/5
description TEST
switchport access vlan 503
interface Vlan503
description TEST
ip address xxx.xxx.xxx.xxx 255.255.255.252
no ip redirects
no ip unreachables
You can redistribute your customers subnet with redistrubute connected or with passive-interface on OSPF/ISIS.