11-05-2008 01:07 PM - edited 03-04-2019 12:12 AM
I have multiple WAN sites with dual P2P T-1 links between them. Right now, we are doing load balancing on them which isn't using bandwidth efficiently due to most of the traffic only going to a handful of destination IP addresses. I would like to use MLPPP to span the links instead, but I didn't know if:
1. That would adversly impact VOIP traffic.
2. If there is any magic to provisioning the lines.
The T-1 circuits are conventionally provisioned data lines from AT&T, and the routers are 2851's with two VWIC-1MFT-T1 cards in them. Any insight or configuration tips would be appriciated. Mike Morgan - Network Engineer.
11-05-2008 01:56 PM
Hello Mike,
I have clarification question. Is this circuit MPLS or P2P? The reason I asked is if it is MPLS that would mean that ATT PE would need to also support MLPPP. This might be a bit off topic to your question but I wanted to bring that up.
The link below might help
http://www.cisco.com/en/US/tech/tk652/tk698/technologies_tech_note09186a0080094660.shtml#link_frag
11-05-2008 03:42 PM
The circuits are P2P conventional T-1s. We haven't moved to MPLS as our needs have only been about 2Mb average. Thanks for the reply! Mike
11-06-2008 05:24 AM
Mike
I would not think that configuring the links for PPP multilink would have any impact on VOIP. The configuration is fairly simple. You configure the multilink interface which is a virtual interface and where the IP address is configured. It would look something like this:
interface Multilink1
ip address x.x.x.x 255.255.255.252
ip virtual-reassembly
no keepalive
no cdp enable
ppp multilink
ppp multilink group 1
and on the physical interfaces you make sure the encapsulation is ppp, remove the IP address and assign them to the multilink:
interface Serial0/0
description multilink connection to xxx
no ip address
encapsulation ppp
no fair-queue
no cdp enable
ppp multilink
ppp multilink group 1
interface Serial0/1
description multilink connection to xxx
no ip address
encapsulation ppp
no fair-queue
no cdp enable
ppp multilink
ppp multilink group 1
HTH
Rick
11-07-2008 07:34 PM
Maybe MLPPP isn't your best choice here, alternate solutions are always worth a look.
An example is a new Cisco Express Forwarding feature that balances traffic across multiple links with the twist that it includes source and destination ports in the path selection decision. Its a "12.4" "T" train feature that is easy to implement and works great. Upgrade the IOS and add one command, its that simple.
http://www.cisco.com/en/US/docs/ios/ipswitch/configuration/guide/cef_load_balancng.html
ip cef load-sharing algorithm {original | tunnel [id] | universal [id] include-ports {source [id] | [destination] [id] | source [id] destination [id]}}
Example:
Router(config)# ip cef load-sharing algorithm include-ports source destination
The reasoning is different conversations use different source/destination pairs, simple actually and brilliant at the same time.
Cheers,
Brian
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