QoS Desing Question

[jpdeboer1]

Hi,

Hope i am in the wright place for this question.

I have a question about QoS. I have one router that will have a separate GRE tunnel to multiple vessels. So if i have 50 vessel i will have 50 GRE tunnels.

All of the 50 vessels can use the same QoS profile, see below config.

ip access-list extended Example
permit ip any 172.16.10.0 0.0.0.255

class-map match-all Example
match access-group name Example

policy-map Example-Priority-Child
class Example
bandwidth remaining percent 80
queue-limit 2000 ms
class class-default
bandwidth remaining percent 20
queue-limit 2000 ms
policy-map Example-Priority
class class-default
shape average 200000
service-policy Example-Priority-Child

I would like to applie this to all of the 50 GRE tunnels, however i have one thing i am not sure about. 

Will the 50 GRE tunnels share the same 200Kbits bandwidth pool, or will QoS handle it per tunnel and each tunnel will have its own 200Kbits bandwidth pool ?

Hope its the last one, otherwise i will need to create a separate class map for each GRE tunnnel so each GRE tunnel will have its own 200Kbis bandwidth pool.

Thanks in advance.

JP

[Joseph W. Doherty · Accepted solution]

It depends on interface the policy is applied.  If applied to tunnels (as you note), bandwidth shaping would apply to just that tunnel.  If applied to physical interface tunnels egress, policy, and any shaping, would apply to traffic egressing that interface.

BTW, on some devices, you can have a service policy on both the tunnel and the physical interface.  If supported this can be handy to deal with destination bandwidth limitations, for each tunnel, and for local egress interface bandwidth limitations for all aggregate tunnel traffic.

[jpdeboer1]

Thank you for the quick reply. 

So if i understand correctly, i apply the same policy on 50 different GRE tunnels which are on the same router configured the policy will handle each tunnel separately and each tunnel will have a 200 Kbits speed limit ?

So not all GRE tunnels will share the same 200 Kbits limit, because this will give an issue when 3 tunnels use the full 200 Kbits the remaining 47 tunnels will have not bandwidth...

[lpassmore]

So, as Joseph said, if you apply the policy to a single tunnel interface then the traffic that pertains to that tunnel will be shaped to 200Kb.  

If every tunnel has the same policy configuration then, assuming you have sufficient overall bandwidth on your link, every tunnel will be shaped individually to 200Kb. 

If you have don't have 50*200Kb available on the link then some tunnels might be starved of bandwidth as they are trying to communicate.

[jpdeboer1]

Thank you for confirming, I also ran a test in VIRL with  multiple tunnels and Iperf and saw all the tunnels were getting the 200k.

Overall bandwidth is no problem, these tunnels are only used as backup for when VSAT goes down.

Thanks again!