Slow upload speed on GRE 6500

[dnsroot13]

Hello Guys,

there is a GRE tunnel configured and 6500 is configured with PBR to route the subnet for GRE.

total download and  upload speed is 100 mbps however with GRE getting 100 Mbps download but only 30 mbps upload speed.

same traffic without gre is getting both 100/100 speed.

the link is WiMAX link terminated on ASA and gre is configurd on 6500 with PBR.

kindly let me know if anybody face this kind of behavior  issues.MTU size I am planning to put for GRE to 1476 and test it from user PC

shall TCP-MSS should be considered as well .attached is the config

[Philip D'Ath]

It may be fragmentation.  If you use smaller packets do you have the same throughput issue?

[dnsroot13]

The throughput is testing with speed test website only which shows download and upload speed

[Philip D'Ath]

Try adjusting the MSS.

I also see you are using policy routing. Are you able to find a way to test with this turned off?

[dnsroot13]

Thanks,MSS on Tunnel interface ? as LAN is behind the SVI's.

without PBR traffic will go with default routing only not with GRE .

[Philip D'Ath]

Yes, you can put theMSS adjust on the Tunnel.

Could you create a static route to a site with a large file on it via the Tunnel and remove the PBR temporarily, and do a test download?  I'm curious if the PBR might be causing this issue.

[dnsroot13]

Thanks ,Let me have a try tomorrow and will get back to you

[dnsroot13]

Without PBR having static route towards the tunnel works great and having good upload speed now :)

now is there any limitation of having PBR for this speed issue ?

Cisco IOS Software, s72033_rp Software (s72033_rp-ADVENTERPRISEK9_WAN-M), Version 12.2(33)SXI10, RELEASE SOFTWARE (fc2)

Technical Support: http://www.cisco.com/techsupport

Copyright (c) 1986-2012 by Cisco Systems, Inc.

Compiled Thu 13-Sep-12 22:28 by prod_rel_team

ROM: System Bootstrap, Version 12.2(17r)SX5, RELEASE SOFTWARE (fc1)

[Philip D'Ath]

We have now narrowed it down to just a single feature causing the issue, so this is a great step forwards.

Could you post the access list you are try to match on.  Also I can see you have a 6500, but I'm not sure which supervisor you are using with it.  Can you post a "show inventory" showing the chassis type and exact supervisor please.

[dnsroot13]

Below are the details.

interface Vlan9
 ip address 10.10.9.2 255.255.255.0
 ip pim sparse-mode
 ip route-cache policy
 ip policy route-map LON
 standby 0 ip 10.10.9.1
 standby 0 priority 120
 standby 0 preempt


route-map LON permit 30
 match ip address FLR
 set ip default next-hop 10.110.100.10 (opposite site of the tunnel) which is further connected to ASA having internet link


ip access-list extended FLR
 permit ip host 10.10.9.50 any
 permit ip host 10.10.3.36 any
 permit ip host 10.11.16.13 any
 permit ip host 10.11.16.14 any
 permit ip host 10.10.3.11 any
 permit ip host 10.10.3.12 any

SUP detail are as below

NAME: "WS-C6513", DESCR: "Cisco Systems Catalyst 6500 13-slot Chassis System"

 7    2  Supervisor Engine 720 (Active)         WS-SUP720-3B       

  8    2  Supervisor Engine 720 (Hot)            WS-SUP720-3B  

[dnsroot13]

Below are the details.

interface Vlan9
 ip address 10.10.9.2 255.255.255.0
 ip pim sparse-mode
 ip route-cache policy
 ip policy route-map LON
 standby 0 ip 10.10.9.1
 standby 0 priority 120
 standby 0 preempt


route-map LON permit 30
 match ip address FLR
 set ip default next-hop 10.110.100.10 (opposite site of the tunnel) which is further connected to ASA having internet link


ip access-list extended FLR
 permit ip host 10.10.9.50 any
 permit ip host 10.10.3.36 any
 permit ip host 10.11.16.13 any
 permit ip host 10.11.16.14 any
 permit ip host 10.10.3.11 any
 permit ip host 10.10.3.12 any

SUP detail are as below

NAME: "WS-C6513", DESCR: "Cisco Systems Catalyst 6500 13-slot Chassis System"

 7    2  Supervisor Engine 720 (Active)         WS-SUP720-3B       

  8    2  Supervisor Engine 720 (Hot)            WS-SUP720-3B  

[Philip D'Ath]

I don't think there is anything wrong with your PBR.

You could try experimenting with the "ip route-cache policy".  Try turning that off, or using a different cache policy.  It is something to do with PBR.

The closest gold star release to the version you have is  12.2.33-SXJ10.  The most recent gold star release is 15.1.2-SY6.

If you are able to upgrade, I would probably go to 15.1.2-SY6.  Otherwise play with different options for the route-cache policy to see what (if any) impact that there is.

[dnsroot13]

turned off but no luck.same issue

checking now release notes for any bugs

[Philip D'Ath]

This is the way I put it to my customers.  A gold star release is particular release that Cisco recommends running.  Do you want to run a release recommend by Cisco?

[dnsroot13]

I would prefer however need to know is  there any existing limitation on the current version of this behavior (if you can trace it out let me know ,I am also checking the same ) and straight away without any findings its difficulty to proves that