[c-nsp] bonded T1s into 7206VXR

[Mark Kent]

>> I am considering getting 4.5M bonded T1 service from AT&T. 

I can think of six ways that this "bonded" service
could be delivered:

1) a csu/dsu that takes multiple T1 and spits out a hssi port
   that is indistinguishable from a hssi port on the
   router side of a (fract-)DS3 csu/dsu.
   
2) MLPPP

3) int sX/Y
     ip load-sharing per-packet

4) ATM imux

5) int sX/Y
     no ip route-cache
   and route equally out each each interface

6) int sX/Y
     ip route-cache
   and route equally out each each interface

I've ordered them according to my preference.

>> will this bonded T1 service act like a single circuit?

The answers are

1) yes
2) yes, with some cpu load,
   and will take care of out-of-order packets
3) yes, with some cpu load
4) yes, with that annoying ATM overhead, better get 4xT1
5) not sure; I'm not sure what the difference is
   between this one and 3).
6) No.

>> I am also wondering if the bonding will work any differently if the
>> (3) T1's are across (2) PA-MC-2T1 cards vs a single PA-MC-4T1 card

I'm 99% sure the answer is No, it won't be different.  Note that you
need a different card for 1) and 4).  And none of these actually
requires the MC part of the T1 port, although I understand you get a
built-in csu/dsu in that case.

-mark