Bonding 2 T-1s

[mbjohnson]

Currently have a remote branch with a 1760 and a T1 doing a IPSec vpn tunnel to a 3660. I would like to add a 2nd T1 on the 1760 and bond them to get 3Mbps and still maitain the vpn tunnel. What's the recommendation? Use PPP Multilink or CEF? Any config examples?

Thanks!

[tbaranski]

I think Multilink PPP is a better bet for load sharing, but it can increase CPU utilization in some cases to a greater extent that is desirable. So I generally recommend trying MLPPP first, and if CPU usage becomes too high, revert to per-packet CEF instead.

(I'm assuming you have a hardware VPN encryption module in the 1760, as I don't think a 1760 could saturate even a single T1 doing software 3DES encryption.)

[mbjohnson]

Thanks for the reply, and yes we do have the vpn aim module in the 1760. Do you know where I could find some config examples by chance?

[adityakaul]

MLPPP cfg

But keep an eye on Cpu.

interface Multilink1

ip address a.b.c.d

load-interval 30

no cdp enable

ppp multilink

multilink-group 1

interface serial 1/0:1

no ip address

encapsulation ppp

ppp multilink

multilink-group 1

interface serial 1/0:2

no ip address

encapsulation ppp

ppp multilink

multilink-group 1

CEF Per-packet-loadsharing...Check if Cef is supported.

ip CEF

interface serial 1/0:1

ip address a.b.c.d

ip load-sharing per-packet

interface serial 1/0:2

ip address a.b.c.d

ip load-sharing per-packet