Topic '[Config] QoS Help' in forum 'Cisco' - dslreports.com

Re: [Config] QoS Help

Thu, 05 May 2016 07:26:40 EDT

tubbynet posted : a switch without mls qos enabled, will basically forward all traffic received without remarking.
turning on mls qos allows all packets to be untrust unless specifically trusted.

that being said -- turning on mls qos turns the already aenemic queue of the 3750 into even smaller queues, by default. this takes some tuning and tweaking to overrride.

q.
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Re: [Config] QoS Help

Thu, 05 May 2016 07:17:36 EDT

bclbob posted : more testing shows the Auto-QoS config from Cisco is good enough - while I don't like random config that I don't know how it works out there, I don't have the energy or time to do this manually.

Re: [Config] QoS Help

Wed, 04 May 2016 22:59:50 EDT

HELLFIRE posted :

said by DarkLogix:

That said if you know of any 4451's with max licensing that just "fell off a truck" that'd be awesome. ;-)

You and me both DarkLogix :D :D

Regards

Re: [Config] QoS Help

Wed, 04 May 2016 17:24:24 EDT

DarkLogix posted :

said by bclbob:

IPbase. I didn't care when I bought them as I don't have any L3 plans for them...

It does take the service-policy commands, just without affect.

I'm not sure if QOS is any different between the feature sets, though if so you'd only need one with services added to the stack to have those features.

But ya I'm fairly sure that QOS wouldn't be any different.

Also I'd expect it to take the commands (though haven't tried) because it's the same IOS image.
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Re: [Config] QoS Help

Wed, 04 May 2016 16:10:03 EDT

bclbob posted : IPbase. I didn't care when I bought them as I don't have any L3 plans for them...

It does take the service-policy commands, just without affect.

Re: [Config] QoS Help

Wed, 04 May 2016 13:07:13 EDT

DarkLogix posted :

said by bclbob:

if I could get the 3750E to mangle the packets from comcast appropriately that would be perfect.

BTW are those 3750E's IPbase or IPservices?
Though not sure if there's a QOS feature difference off hand.

Re: [Config] QoS Help

Wed, 04 May 2016 13:06:31 EDT

DarkLogix posted :

said by HELLFIRE:

I'd have to test that on my lab 3750 to confirm the exact syntax... but for that kind of stuff I'd prefer to do it on an ISR rather than a layer 3 switch myself...

Good luck getting an ISR that can do 2gbps and fit in the budget.

That said if you know of any 4451's with max licensing that just "fell off a truck" that'd be awesome. ;-)
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A plan that doesn't scale is a plan to fail.

Re: [Config] QoS Help

Wed, 04 May 2016 08:17:12 EDT

bclbob posted :

said by markysharkey:

Can't get my head around this. Surely unless the inbound interface is set to trust COS markings they will be reset to 0?

And that is what was happening when I was enabling QoS with the global 'mls qos' command. But then I discovered this caused performance issues with traffic leaving my TenGigabitEthernet interfaces and was asking for more help with either configuring QoS or disabling QoS and coming up with another way to reset the frames to 0 (such as a service policy).

But it looks like I've mitigated the TenGigabitEthernet issue by configuring Auto-QoS.

Re: [Config] QoS Help

Tue, 03 May 2016 17:26:45 EDT

markysharkey posted : Can't get my head around this. Surely unless the inbound interface is set to trust COS markings they will be reset to 0?
I don't see

mls qos trust cos

on the inbound interface so once frame has moved from the interface to the backplane fabric the CoS should be set to 0. Can you Wireshark frames as they are output from a different interface.
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Re: [Config] QoS Help

Tue, 03 May 2016 17:08:25 EDT

bclbob posted : I don't know how to get the WLC to dump its config! show running-config just gives lots of info, more like show tech-support

I'd have to test that on my lab 3750 to confirm the exact syntax... but for that kind of stuff I'd prefer to do it on an ISR rather than a layer 3 switch myself...

Regards

unfortunately an ISR that could handle 10 gig is a little out of my price range... if I could get the 3750E to mangle the packets from comcast appropriately that would be perfect.

Re: [Config] QoS Help

Mon, 02 May 2016 18:39:47 EDT

HELLFIRE posted :

said by bclbob:

the TOS is showing as 0x20 from comcast ... Applying QoS makes that become 0x0 and the WLC/LAP's work great.

Ahh, so basically you need all packets FROM comcast TO your wifi to have TOS 0x0, okay that makes sense.

said by bclbob:

I don't know if its CS1 or CS2, googling seems to not give me a good answer either.

This help?

said by bclbob:

When I was running the Cisco 3845 I was able to fix it using a service-policy but it doesn't appear to work on the 3750Es

I'd have to test that on my lab 3750 to confirm the exact syntax... but for that kind of stuff I'd prefer to do it on an ISR rather than a layer 3 switch myself...

Regards

Re: [Config] QoS Help

Mon, 02 May 2016 18:29:08 EDT

bclbob posted : forgive my decoding, the TOS is showing as 0x20 from comcast and that causes the bad behavior to happen. Applying QoS makes that become 0x0 and the WLC/LAP's work great.

I don't know if its CS1 or CS2, googling seems to not give me a good answer either. I'm not a layer 2 expert by any means!

Let me post the WLC config in a bit, but I just wanted to clarify the TOS value.

Here's a link to the issue: »www.reddit.com/r/network ··· ustomer/

When I was running the Cisco 3845 I was able to fix it using a service-policy but it doesn't appear to work on the 3750Es .... maybe the service-policy only works on L3 interfaces?

it looked like this:

class-map match-all comcast-dscp-cs1 match ip dscp cs1policy-map policy-comcast-dscp-cs1  class comcast-dscp-cs1    set ip dscp default int gi0/0  service-policy input policy-comcast-dscp-cs1

Re: [Config] QoS Help

Mon, 02 May 2016 17:53:34 EDT

HELLFIRE posted :

said by bclbob:

edit: or how to configure the WLC/LAP access points to not de-prioritize the CS1 traffic?

Able to supply the config of the WLC/WAP in question?

Offhand, if it's a "standard" config with no specifics for QOS, the WLC/WAP should just honor the markings and move on.

And the thing that gets me is your comment "comcast is putting 'CS1' QoS on their incoming traffic." IIRC, CS1 is 001000
(decimal 8) which is "only" slightly below AF11 001010(decimal 10). Also, when you say "incoming traffic" do you mean
FROM the internet to your LAN, or vice versa? Never mind, reading your wireshark which answers that...

My initial 00000010bits

Regards

Re: [Config] QoS Help

Mon, 02 May 2016 17:42:34 EDT

bclbob posted : ok: I seem to have it better / fixed on the 10 gig ports by setting up Auto QOS. oh well, some black magic somewhere.

[Config] QoS Help

Mon, 02 May 2016 10:23:50 EDT

bclbob posted : Spotted a problem with my network. It comes down to the fact that comcast is putting 'CS1' QoS on their incoming traffic. Unfortunately this CS1 is honored by the Cisco WLC/1252 APs and causes low download performance over wifi.

If I set QoS 'mls qos cos override' on the interface like so:

interface TenGigabitEthernet1/0/1 description CMST 10G fiber switchport access vlan 239 switchport mode access switchport nonegotiate bandwidth 2097152 ip arp inspection trust mls qos cos override spanning-tree portfast ip dhcp snooping trustend

it will fix the slow performance on Wifi. But now I've discovered it halves the upload performance on wired clients, so I guess I need more settings on QoS. Any ideas what QoS settings I need on wired ports?

edit: or how to configure the WLC/LAP access points to not de-prioritize the CS1 traffic?

edit2: another clue, it seems to be only affecting traffic leaving the 10Gbit interfaces

edit3: example tcpdump of what is coming in from comcast

13:59:34.178165 IP (tos 0x20, ttl 48, id 47385, offset 0, flags [none], proto TCP (6), length 60)
157.166.226.26.80 > 172.31.90.124.57380: Flags [S.], cksum 0x70f9 (correct), seq 3997761681, ack 3842517183, win 5792, options [mss 1380,sackOK,TS val 3912008694 ecr 991409399,nop,wscale 7], length 0