01-06-2009 07:42 AM - edited 03-04-2019 03:21 AM
Hi All,
I was hoping someone could help me with a load balancing issue I'm having.
Brief network setup:
Customer has a Point to point serial T1 to our primary datacenter on RTR 2.
Customer has a Frame relay -> ATM T1 to our secondary datacenter.
Primary datacenter is connected secondary via 100mb fiber AND a 1mb ATM PVC. The ATM PVC is on RTR 1 and the Fiber connection is just a Layer 2 connection.
I would like to Load balance downstream traffic across the PTP and FR connections. I've been able to load balance upstream traffic, but downstream isn't being so cooperative.
The included .jpg is a rough sketch of our network with pertinate information including topology, IPs, and interface configs... sanitized of course.
Also included are the show ip eigrp topology output for the desired network (10.220.23.0/24).
If I change the bandwidth statement on the 1mb cross-connect PVC (see diagram), that becomes the primary route for quite a few routes, which is not desired. I'm guessing this is because of the value that's set for delay.
Any thoughts how I could get some downstream load balancing across these circuits?
Solved! Go to Solution.
01-06-2009 11:32 AM
Hello Ryan,
you need to increase delay on the direct link in order to get a chance to load balance
as you can see on the sh ip eigrp topology
10.2.150.2 (ATM2/0.4034), from 10.2.150.2, Send flag is 0x0
Composite metric is (1713920/1709056), Route is Internal
Vector metric:
Minimum bandwidth is 1500 Kbit
Total delay is 290 microseconds
Reliability is 255/255
Load is 1/255
Minimum MTU is 1500
Hop count is 1
10.2.200.1 (ATM2/0.4032), from 10.2.200.1, Send flag is 0x0
Composite metric is (3086080/2226176), Route is Internal
Vector metric:
Minimum bandwidth is 1000 Kbit
Total delay is 20550 microseconds
Reliability is 249/255
Load is 3/255
Minimum MTU is 1500
Hop count is 4
Being
State is Passive, Query origin flag is 1, 1 Successor(s), FD is 1713920
you need to increase delay so that the best metric becomes higher and anothe route can pass the feasibility condition FC
To get a more selective effect on only specific routes you can think to use an offset-list inbound
http://www.cisco.com/en/US/docs/ios/iproute/command/reference/irp_eig2.html#wp1012264
you can define with an IP ACL for what routes the metric has to be modified.
this way you can make two paths comparable.
If they are not equal you can use variance to get load-balancing over them (weighted)
Hope to help
Giuseppe
01-06-2009 11:32 AM
Hello Ryan,
you need to increase delay on the direct link in order to get a chance to load balance
as you can see on the sh ip eigrp topology
10.2.150.2 (ATM2/0.4034), from 10.2.150.2, Send flag is 0x0
Composite metric is (1713920/1709056), Route is Internal
Vector metric:
Minimum bandwidth is 1500 Kbit
Total delay is 290 microseconds
Reliability is 255/255
Load is 1/255
Minimum MTU is 1500
Hop count is 1
10.2.200.1 (ATM2/0.4032), from 10.2.200.1, Send flag is 0x0
Composite metric is (3086080/2226176), Route is Internal
Vector metric:
Minimum bandwidth is 1000 Kbit
Total delay is 20550 microseconds
Reliability is 249/255
Load is 3/255
Minimum MTU is 1500
Hop count is 4
Being
State is Passive, Query origin flag is 1, 1 Successor(s), FD is 1713920
you need to increase delay so that the best metric becomes higher and anothe route can pass the feasibility condition FC
To get a more selective effect on only specific routes you can think to use an offset-list inbound
http://www.cisco.com/en/US/docs/ios/iproute/command/reference/irp_eig2.html#wp1012264
you can define with an IP ACL for what routes the metric has to be modified.
this way you can make two paths comparable.
If they are not equal you can use variance to get load-balancing over them (weighted)
Hope to help
Giuseppe
01-08-2009 06:23 AM
Thanks for the reply. I'll give it a go.
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