[nsp] Suggestions on terminating a bunch of T1's

Matthew Crocker matthew at crocker.com
Wed Feb 4 15:42:53 EST 2004

Take a look at Seranoa WANPort  (www.seranoa.com).  Basically it is an 
embedded Linux box with an Intel Network Processor.  It can handle a 12 
Channelized DS-3s and break them up into DS1, DS1xN (MPPP), or DS0xN.   
Each DS1 can be either Frame Relay, PPP or HDLC.  The unit strips off 
the HDLC frame and wraps the resulting IP into a dot1q VLAN.  All 
traffic is sent out a GigE port.  You'll need a router to terminate the 
GigE/VLANs for each T1 customer.

With this setup you would need 4 WANPorts (48 ChDS-3s) and a Router 
with 4 GigE interfaces or 4 routers with a GigE each..  A Cisco 
7300/7400 or a Juniper M7i would work pretty well.

I'm testing one out now using a 3550 as my 'router blade'  once I get 
enough traffic through it I'll replace the 3550 with a 7300/7600 or 

Customer IP traffic will flow like this

IP from computer -> ETH(IP) -> Customer Router -> HDLC(IP) -> WANPort 
-> dot1q(IP) -> Your router -> IP routing decision.

Frame Relay DLCIs are handle the same way,  unwrap the DLCI frame and 
wrap it back up in a dot1q frame.  The WANPort is entirely Layer2,  
doesn't care about the payload, All traffic on a VLAN goes to the 
customer, All traffic from customer goes to a VLAN.  The WANPort CLI is 
very IOSish

Using a 454 doesn't make sense. The XC-VT card can only groom an OC-12s 
worth of DS-1s. You would need 4 454 chassis to handle the grooming.  
You are better off with M13s (www.carrieraccess.com  WideBank 28s are 
good and cheap)

Using M13s to build ChDS3s and running them into a WANPort to groom 
everything down to GigE.  Buy a high end GigE router in a pizza box and 
terminate the IP sessions.  The only flaw I can see is the loss of 
direct DS-1 into router so you can't tell if the link is down and 
remove the route.  If a customer has multiple T1s you'll need to us 
MPPP (on the WANPort) or OSPF (router to router) to handle failover.

Contact Jeff Rose (978) 206-2000 for Seranoa Sales.  Tell him I said hi 

Disclaimer:  I don't work for Seranoa and I don't make a commission 
from them.  I have yet to use their equipment in a production 
environment but testing looks pretty good.  I'm building out some other 
bits and pieces and hope to have it in production later this month.  
They are a young company with a cool product.


Matthew S. Crocker
Crocker Communications, Inc.
Vice President
PO BOX 710
Greenfield, MA 01302

P: 413-746-2760
F: 413-746-3704
W: http://www.crocker.com
E: matthew at crocker.com

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