Bonding T1 lines 2

[Kenny56]

I have 2 T1 lines that are on separate routers currently. One is being used live by our Corporate office as the gateway to the internet while the other line is a backup. I would like to bond the two lines in efforts to maximize our bandwidth.

How could I accomplish this?

 

[l3stuff]

Multichassis Multilink PPP (if you want to keep them on different routers and the ISP routers can handle is (doubtful), or CEF based load balancing (equal cost paths) if they are on the same router

 

[Kenny56]

l3stuff

If I were to put them on the same router would it be easier?

Thanks in advance,

Kenny56

 

[l3stuff]

very much so

 

[Kenny56]

l3stuff,

I have a Cisco 1720 with an extra DSU Wic. Is it just a matter of conneting the 2nd T1 line to the Extra DSU wic on the 1720 and assigning both interfaces the same IP?

Or is the process a little more extinsive.

Thanks again for you help,

Kenny56

 

[gaveeve]

What routing protocol are you using? If for example both your routers are cisco and you were using eigrp you could use the variance command which with some tweaking could enable both links. You could still use both routers.

 

[Kenny56]

gaveeve, l3stuff,

I would rather bond the 2 T1s using one router. Could anyone give me some insight on how I could accomplish this.

Thanks in advance,

Kenny56

 

[l3stuff]

Multilink ppp "bundles" the interfaces into a single logical circuit. This has a processing overhead, and requires both ends (both routers) to participate.

CEF load balancing is routing protocol independant (EIGRP allows for unequal cost paths) and allows for up to 6 parallel paths. It is not dependant on the other end. Low overhead.

 

[camercad]

I am wanting to do the same thing with a different router. I have a 7200 core router and a 2621 at the remote site. I have a Wic-1DSU-T1 card in it now and would like to add a second and bond them. These are private line Point to point circuits. Would this be a simple config?

 

[JoeBloggssss]

Hi,

Buy an inverse multiplexer.

 

[JOAMON]

Hello....
I recentley bonded two t1 ponit to point connections using a cisco 2611 and 2811 with the following config on each router. Hope this is useful.

!
interface Multilink1
ip unnumbered Ethernet0/0 (lan interface)
ip nat inside
no cdp enable
ppp multilink
no ppp multilink fragmentation
ppp multilink group 1
!
interface Serial0/0
no ip address
encapsulation ppp
tx-ring-limit 26
tx-queue-limit 26
no keepalive
no fair-queue
ppp multilink
ppp multilink group 1
!
interface Serial0/1/0
no ip address
encapsulation ppp
tx-ring-limit 26
tx-queue-limit 26
no keepalive
no fair-queue
no cdp enable

Also make sure to add appropriate ip route to each config to reach the other router via multilink interface.

 

[JOAMON]

Config got cutoff in last post....
make sure both interfaces are configured same as serial0/0 in last post.

 

[camercad]

Thanks JDAMON
Thats the info that I was looking for.

 

[JOAMON]

Keep in mind that the configuration I listed was for two point to point t1 lines. I also have it setup with two t1 lines to the internet. Check with your ISP to make sure they can support a multilink connection. The only real difference is that the multilink has static ip instead of ip unnumbered which is talking to the ISP multilink interface and remove ip nat inside. I have a seperate router used to connect to my ISP's multilink router. It's ethernet port uses my 1st ip routeable address. The 2811 uses one ethernet with 2nd ip routeable using the 2611 as default next hop router. The other port connects to the lan side.