10-25-2011 02:37 AM - edited 03-04-2019 02:02 PM
Hi all,
We added following config to track VSAT links. But the problem is whenever VSAT bandwidth is FULL, track is getting failed automatically and automatically default route switching over to dialup.
Once the traffic is started to flow though dialup link VSAT bandwidth is coming to low and track will get success. Then default route is switching over to VSAT.
This happening again and agin. please guide me to resolve this track flapping issue.
SLA config :
ip sla 109
icmp-echo 172.16.0.1 source-interface Tunnel10
timeout 6000
frequency 10
ip sla schedule 109 life forever start-time now
Track config :
track 109 ip sla 109 reachability
route config :
ip route 0.0.0.0 0.0.0.0 Tunnel10 track 109
ip route 0.0.0.0 0.0.0.0 tunnel5 50
10-25-2011 02:47 AM
Hi,
Maybe you could shape traffic going over VSAT so bandwidth is never FULL.
Regards.
Alain.
03-12-2012 08:54 AM
Hi,
I get this a lot too. What I did in the end was configure the IP SLA to use a TOS (Type of Service ) value. You configure it under the ip sla object itself. e.g.
ip sla 109
icmp-echo 172.16.0.1 source-interface Tunnel10
tos 184
timeout 6000
frequency 10
ip sla schedule 109 life forever start-time now
There is a matrix for TOS values and how it is respresented in DSCP etc. 184 is basically DSCP 46 or Expedited Forwarding. By setting the TOS value on the IP SLA packets it'll now get expeditited out of the router faster. Crucially of course you ALSO need to create a QOS framework on your router to manage the packets so that your SLA gets pushed out above all the others.
So a basic MQC might look like this (forgive me I'm writing this from my head). Basically I'll be permitting the SLA traffic 8kbps (which is more than enough) as priority traffic and then shaping all other traffic to 98% of the line rate. You'll need to set the correct 'bandwidth' statement under the interface facing the VSAT (i've suggested 2Mbps). I noticed you are using a tunnel interface in your statement so you'll also need to use the 'qos pre-classify' statement in that logical interface.
class-map SLA
match dscp ef
policy-map SHAPER
class SLA
priority 8
class class-default
shape average 98%
interface G0/0
service-policy output SHAPER
bandwidth 2048000
interface tu10
qos pre-classify
Hope this helps
Rich
03-12-2012 04:15 PM
Alteranitely if you do not want to configure qos to the router you can use to the static route a track with multiple sla.
So, the static route will removed if all the sla (so all the packets) fail on the same time.
You can achieve this if you configure a Tracked List and Boolean Expression.
A tracked list contains one or more objects. The Boolean expression enables two types of calculation by using either "and" or "or" operators.In your case you need to use "and" and as many sla as you think are needed in order to overcome your problem
You can find detailed examples to the next link:
http://www.cisco.com/en/US/docs/ios/12_2t/12_2t15/feature/guide/fthsrptk.html
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide