06-06-2007 01:44 PM - edited 03-03-2019 05:20 PM
Need help getting per packet loadbalancing working over two t1s, two cisco 1700 routers on each end...
I have cef enabled with the following interface configs.
It works, but is only doing per destination balancing
interface Multilink20
description MLP to TLC Multilink20
ip address 10.97.23.2 255.255.255.252
no ip redirects
no ip proxy-arp
ip load-sharing per-packet
ip pim sparse-dense-mode
fair-queue
ppp multilink
ppp multilink links minimum 1
ppp multilink group 20
!
interface FastEthernet0/0
ip address 10.20.254.235 255.255.0.0
speed 100
full-duplex
!
interface Serial0/0
description T1 to TLC Se0/0 T1 ID 11-DHXS-000650
bandwidth 1544
no ip address
ip load-sharing per-packet
ip pim sparse-dense-mode
encapsulation ppp
no fair-queue
service-module t1 timeslots 1-24
service-module t1 fdl att
ppp multilink
ppp multilink group 20
!
interface Serial1/0
description T1 to TLC Se0/1 T1 ID 11-DHXS-000650
bandwidth 1544
no ip address
ip load-sharing per-packet
ip pim sparse-dense-mode
encapsulation ppp
no fair-queue
service-module t1 timeslots 1-24
service-module t1 fdl att
ppp multilink
ppp multilink group 20
06-06-2007 06:26 PM
MICHAEL
I am very curious to know how you have determined how you distinguish on the multilink whether it is doing per packet or per destination load balancing.
With multilink there is only 1 logical path between the routers and per packet or per destination result in the same behavior: all traffic is sent over the 1 logical link between the routers.
HTH
Rick
06-07-2007 04:53 AM
Yes Rick,
what ever i know is if you have 4 link and you creat the logical Mulitlink interface for all that 4 link then arrived packet is fragmented in 4 subpacket and those packets will travel through those 4 links...
regards
Devang
06-07-2007 05:25 AM
with cef enabled, it should be per packet load balancing.
06-07-2007 05:51 AM
The reason I believe it is doing per destination load balancing is because I have two t1's, and when I start up an ftp over the MLPPP I am only getting a max throughput of 1.5MB, never anymore. Lead me to believe the it is doing per destination and send all traffic over one link.
I have CEF enable, and routes point to the MLPPP interface on both sides.
Any thoughts...should I be doing fragmentation?
thanks,
06-07-2007 06:12 AM
MICHAEL
I am surprised that you would not get more than T1 throughput. I do not believe that it is a matter of load balancing. Since there is 1 logical path between the routers there is no balancing to be done.
I wonder if there might be an issue on one of the links that is impacting throughput. Could you post the output of show interface for all the serials interfaces involved, the output of show service-module, and the output of show ppp multilink. It would be best if we could see these outputs from both routers.
Without knowing a bit more about your environment and the mix of traffic going over the multilink we can not say whether fragmentation would be beneficial. My guess is that it will not matter. Of course you could configure it and see if any behavior changes.
HTH
Rick
06-07-2007 06:25 AM
06-07-2007 06:48 AM
MICHAEL
Thanks for posting the additional output. It does not show anything abnormal. I notice that the interface output and the service module output were cleared and show the last 5 or 6 minutes only. Would I assume that you cleared them and ran the test again?
The output shows that both T1s are approximately equally balanced and both are carrying load. So it looks like the multilink is working correctly (and there is no load balancing issue). I am wondering if there could be some other factor that is constraining the throughput of your FTP transfer.
HTH
Rick
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