02-23-2007 02:15 AM - edited 03-05-2019 02:32 PM
Hello
I have the following scenario
N. 2 Router 7513
N.2 ATM link of 24 Mb/s
In this two links the traffic ( the Ospf cost is the same and is set to default)pass for 90% only on the one link
ATM and the other is around 10%.
The problem is to balance this two WAN ATM Links ...
I would like to have 60 % and 40 % on the two links is it possible using OSPF ??( I know its possible under BGP )
Any suggestion is appreciated !
Regards
Alberto
FIRST ATM
interface ATM8/1/0.33 point-to-point
description PVC verso TO0MA02P P2/8
bandwidth 24000
ip address 10.224.0.x 255.255.255.252
ip mtu 1500
pvc 0/33
vbr-nrt 26400 24000 33
oam-pvc manage
oam retry 3 3 3
encapsulation aal5snap
Second ATM (90% of traffic )
interface ATM8/1/0.36 point-to-point
description PVC verso TO0MA02P P3/10 ---
bandwidth 24000
ip address 10.224.0.x 255.255.255.252
ip mtu 1500
pvc 0/36
vbr-nrt 26400 24000 33
oam-pvc manage
oam retry 3 3 3
encapsulation aal5snap
++++++++++++++++++++++++++++
Routing ( similiar for both routers)
router ospf 69
log-adjacency-changes
area 9 range 10.156.0.0 255.255.192.0
area 9 range 10.156.64.0 255.255.192.0
area 9 range 10.156.128.0 255.255.192.0
area 9 range 10.156.192.0 255.255.192.0
network 10.156.215.0 0.0.0.15 area 9
network 10.156.215.16 0.0.0.15 area 9
network 10.156.255.52 0.0.0.3 area 9
network 10.156.255.76 0.0.0.3 area 9
network 10.156.255.0 0.0.0.255 area 9
network 10.224.0.112 0.0.0.3 area 0
network 10.224.0.116 0.0.0.3 area 0
network 10.224.1.36 0.0.0.3 area 0
network 10.255.0.15 0.0.0.0 area 9
!
02-23-2007 02:24 AM
Hello,
can you post the routing tables as well?
OSPF will load balance two pathes with exact the same metric by default. In addition you need to check your CEF load balancing, which is deciding, which traffic goes through which link if both pathes are in the routing table.
The default is "per destination" but can be changed to "per packet". So a traffic analysis might help to understand the different load on the two links.
A good starting point for reading is "How Does Load Balancing Work?"
http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094820.shtml
and "Load Balancing with CEF"
http://www.cisco.com/en/US/products/hw/modules/ps2033/prod_technical_reference09186a00800afeb7.html
Hope this helps!
Regards, Martin
02-23-2007 02:30 AM
Hello
thanks you for yor prompt reply
The routing table is a list of 3 pages !!!!
We have around 700 cisco in our WAN
The point of Cef was also considered . You intend that I have to change the Ip cef per destination and then analyze the traffic?
Or this can also distribuite better the balancing over this 2 links?
Thanks a lot !
02-23-2007 02:32 AM
wpoz-noc-01-abr# sh ip cef 10.55.207.11
10.55.192.0/18, version 1256, epoch 0, cached adjacency to ATM8/1/0.36
0 packets, 0 bytes
via 10.224.0.117, ATM8/1/0.36, 0 dependencies
next hop 10.224.0.117, ATM8/1/0.36
valid cached adjacency
Router 2
wpoz-noc-02-abr#sh ip cef 10.55.207.11
10.55.192.0/18, version 9114, epoch 0, cached adjacency to ATM8/1/0.33
0 packets, 0 bytes
via 10.224.0.201, ATM8/1/0.33, 0 dependencies
next hop 10.224.0.201, ATM8/1/0.33
valid cached adjacency
02-23-2007 02:43 AM
Hi,
Thank you for the "sh ip cef" posting of only ONE network :-)
As you have two routers (did not realize this o far), load balancing will be decided elsewhere. Each of your routers will just forward the traffic down its own WAN link. If 90% of all traffic is sent to router one then 90% will go through link 1.
So the real question is: How does the traffic get to the WAN routers? HSRP (f.e. use GLBP instead to achieve better load balancing), OSPF to other routers?
Regards, Martin
02-23-2007 02:56 AM
Dear
I know how GLBP works. But its a LAN side protocols
So I need to replace all the VLAN balancing in the WS-C6513 Switch ( On the routing Module )
Do you think that make a round- robin over a GLBP MULITIGORUP can fix my problem ?
Here it is the scenario in the MSFC of the 6513.
************************************
wpoz-csb-02-cstel#sh standby
Vlan1 - Group 2
Local state is Listen, priority 70, may preempt
Hellotime 3 sec, holdtime 10 sec
Virtual IP address is 10.156.242.254 configured
Active router is 10.156.242.251, priority 200 expires in 7.472
Standby router is 10.156.242.250 expires in 7.320
0 state changes, last state change never
IP redundancy name is "hsrp-Vl1-2" (default)
Vlan10 - Group 10
Local state is Listen, priority 70, may preempt
Hellotime 3 sec, holdtime 10 sec
Virtual IP address is 10.156.205.254 configured
Active router is 10.156.205.250, priority 100 expires in 9.684
Standby router is 10.156.205.251 expires in 9.172
0 state changes, last state change never
IP redundancy name is "hsrp-Vl10-10" (default)
Vlan20 - Group 20
Local state is Listen, priority 80, may preempt
Hellotime 3 sec, holdtime 10 sec
Virtual IP address is 10.156.207.254 configured
Active router is 10.156.207.251, priority 100 expires in 8.260
Standby router is 10.156.207.250 expires in 7.908
0 state changes, last state change never
IP redundancy name is "hsrp-Vl20-20" (default)
Vlan30 - Group 30
Local state is Listen, priority 70, may preempt
Hellotime 3 sec, holdtime 10 sec
Virtual IP address is 10.156.201.254 configured
Active router is 10.156.201.250, priority 100 expires in 8.924
Standby router is 10.156.201.251 expires in 8.504
0 state changes, last state change never
IP redundancy name is "hsrp-Vl30-30" (default)
Vlan40 - Group 40
Local state is Listen, priority 80, may preempt
Hellotime 3 sec, holdtime 10 sec
Virtual IP address is 10.156.211.254 configured
Active router is 10.156.211.251, priority 100 expires in 7.976
Standby router is 10.156.211.250 expires in 7.532
0 state changes, last state change never
IP redundancy name is "hsrp-Vl40-40" (default)
Vlan60 - Group 60
Local state is Listen, priority 70, may preempt
Hellotime 3 sec, holdtime 10 sec
Virtual IP address is 10.156.214.254 configured
Active router is 10.156.214.250, priority 100 expires in 8.956
Standby router is 10.156.214.251 expires in 7.588
0 state changes, last state change never
IP redundancy name is "hsrp-Vl60-60" (default)
Vlan220 - Group 192
Local state is Listen, priority 70, may preempt
Hellotime 3 sec, holdtime 10 sec
Virtual IP address is 10.156.192.254 configured
Active router is 10.156.192.250, priority 100 expires in 8.044
Standby router is 10.156.192.251 expires in 7.556
0 state changes, last state change never
IP redundancy name is "hsrp-Vl220-192" (default)
Vlan221 - Group 193
Local state is Listen, priority 80, may preempt
Hellotime 3 sec, holdtime 10 sec
Virtual IP address is 10.156.193.254 configured
Active router is 10.156.193.251, priority 100 expires in 7.508
Standby router is 10.156.193.250 expires in 7.756
0 state changes, last state change never
IP redundancy name is "hsrp-Vl221-193" (default)
........
....... etc ..etc..
************************
Thanks
02-23-2007 03:40 AM
Hi,
my first question would be to understand why traffic distribution is 90-10 at the moment. Replacing GLBP with HSRP can help from the LAN side. The rest is IP routing. I still do not understand your topology. There is one 6513 as a default gateway with all the PCs connected (through L2 trunks maybe)?
And the 6513 has one link to each WAN router?
Or does it look different? Load balancing is strongly dependant on the underlying topology and involved protocols.
Regards, Martin
02-23-2007 05:38 AM
02-23-2007 02:24 AM
Hello,
can you post the routing tables as well?
OSPF will load balance two pathes with exact the same metric by default. In addition you need to check your CEF load balancing, which is deciding, which traffic goes through which link if both pathes are in the routing table.
The default is "per destination" but can be changed to "per packet". So a traffic analysis might help to understand the different load on the two links.
A good starting point for reading is "How Does Load Balancing Work?"
http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094820.shtml
and "Load Balancing with CEF"
http://www.cisco.com/en/US/products/hw/modules/ps2033/prod_technical_reference09186a00800afeb7.html
Hope this helps!
Regards, Martin
02-23-2007 07:54 AM
Wait for your confirm about my propose:
wpoz-noc-02-abr# conf t
Enter configuration commands, one per line. End with CNTL/Z.
wpoz-noc-02-abr(config)#int ATM8/1/0.33
wpoz-noc-02-abr(config-subif)#ip load-sharing ?
per-destination Deterministic distribution
per-packet Random distribution
wpoz-noc-02-abr(config-subif)#ip load-sharing per-packet
02-23-2007 12:55 PM
I would be careful with per packet load sharing.... In most situations, per packet load sharing will cause TCP packets to be received our of order, which actually produces lower performance even with higher network utilization.
:-)
Russ
02-26-2007 01:09 AM
Hello
so what you suggest ?
GLBP on the LAN side?
This need to modify the whole architecture.
Thanks
Alberto
03-05-2007 05:15 AM
As long as both of the routes are installed in the local routing table, it doesn't matter what routing protocol installs them--OSPF and BGP act the same in this regard. If you are getting 90/10 load sharing, you might want to try the "tunnel" algorithm for per destination load sharing under CEF, as a start.
Another option would be to try and change the "seed" CEF is using to run its load sharing algorithm off of.
:-)
Russ
03-05-2007 10:19 PM
Hi
From the diagram I understand that the 2 routers are not interconnected directly,if done then that would solve the problem.If possible interconnect 2 routers with a cross cable,make them ospf neighbor,tweak the cost for the destination router's loopback(router connected to other end of the WAN link) such that for that loopback address router sees 2 paths one via its own link and second via the second interconnected router.This would cause traffic coming to R1 to be shared with R2 via cross cable.Traffic coming to R2 wont be shared with R1 as tweaking of cost is done only on R1.Thi sshould result in a utilisation of 60/40.
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