QoS info and conf

[b2kzone-beniamin]

Hello guys,

I want to ask you for help and advice regarding the QoS on private network (intranet).

I have a modem form ISP connected ti my cisco router 2611xm that is connected to my switch 2950T and from there from port1(lan1 100mb/s)is connected a access point.

modem(ISP) --> router cisco --> switch cisco --> AP --> host 

Hardware

router cisco 2611XM with os flash:c2600-advsecurityk9-mz.124-15.t14.bin, C2600-ADVSECURITYK9-M, 12.4(15)T14

switch cisco 2950T with os flash:/c2950-i6k2l2q4-mz.121-22.EA14.bin, C2950-I6K2L2Q4-M, 12.1(22)EA14

I want to implement quality of service on both (router and switch) and I need from help form you guys, I'm stuck on the config part, I understand what is QoS and for what is but the config part is killing me.

The things of what I want to do:

-> have a class where to specify that the video and audio traffic to be first, trafic like(youtube, netflix, skype, facebook video-call, and those things that are part of a audio and video)

-> have a class where to specify traffic of data like browsing sites to be second, sites like(facebook, amazon, news, etc)

-> an other class for file transfer to be third (interna file tranfer from nas to pc, between pcs, downloade from sites as a ex if I want do download a os from ubuntu or other sites

-> an other for management traffic

Can someone help me with exmples and info(explane)

[Joseph W. Doherty]

Have you read the configuration guides' QoS chapter for your platforms/IOS?  (NB: such guides may no longer be on Cisco's main site as what platforms you're working with, or using, is so old, but documentation might be found on different, 3rd party, archival sites.)

Wireless QoS, at least last time I looked at it (several years ago) wasn't, IMO, up to snuff and wireless hosts seldom supported it.

Does your ISP modem provide full port speed, for traffic, both up and down?

QoS support on a 26xx router and a 2950 switch can be very different and the latter is generally much more limited in what QoS features it supports vs. the former.  Also the 2950s came in SI and EI variants, the former having an even more limited QoS feature set.  (NB: your IOS name, on the switch, might indicated SI vs. EI, but I no longer recall how to "decode" the filename.)

In any case, if you can answer the couple of questions I've asked, above, we'll see where we might go next.

[b2kzone-beniamin]

hey,

Have you read the configuration guides' QoS chapter for your platforms/IOS 

yes, https://www.manualslib.com/manual/1287341/Cisco-Catalyst-2950.html#page=527-manual but still have problem to config, 

Does your ISP modem provide full port speed, for traffic, both up and down?

yes, 300mb/s down and 150 mb/s up

Also the 2950s came in SI and EI variants, 

I have de (EI)

[Joseph W. Doherty]

Great!

Two things you, I believe, should accomplish are 1) shape traffic slower than port speed where for some reason full port speed is "too fast".  The one instance of that would be your gig interface to the ISP where you only have 150 Mbps up.  The second instance is likely your port that connects to your AP.  (NB: unfortunately, don't believe the 2950 supports "shaping".)

The second thing you should accomplish, is "mark" your traffic, I suggest L3 ToS using DSCP markings.  Your router doesn't really need this, but it's a bit more efficient.  Your switch, though, really needs some form of packet or frame marking/tagging.

On the router, its WAN interface policies would be something like:

policy-map rtr-WAN-Ingress
class real-time
set ip dscp ef
class background
set ip dscp cs1
!class etc
!set ...
class class-default
set ip dscp be

policy-map rtr-WAN-Egress-shape !this is the policy assigned to WAN interface's egress
class class-default
shape average 150000000
service-policy rtr-WAN-Egress-QoS

policy-map rtr-WAN-Egress-QoS
class real-time
priority percent 30
class background
bandwidth percent #
!class etc
!bandwidth percent #
class class-default
bandwidth percent #
fair-queue

For your switch, I believe (?) you might be able to use an interface ingress policy much like the one, above, for your router. However, that policy might allow and/or verify host ToS markings too.

I recall (?) a 2950 does not support an egress policy like your router can. Instead either L2 CoS markings (recommend not to use) or L3 ToS markings can be directed (i.e.) map to hardware egress queues. By default, certain CoS/ToS markings go to specific queues. These assignments can be changed. Also, the hardware queues get a percentage of bandwidth, 25% each (which can also be changed), I believe, by default, although, I also believe, one queue can be made a priority queue (i.e. it always dequeues first). PQ requires activation via configuration (as also does, BTW, by default, QoS itself). PQ should be used for real-time traffic, e.g. VoIP bearer traffic.

Questions?

[b2kzone-beniamin]

hello, and if the scheme is host --> SW --> router --> modem(ISP) the class and the policy remains the same?

[Joseph W. Doherty · Accepted solution]

Logically, you normally try to have a QoS scheme for your whole AD.

Physically, different devices often have different QoS support, especially within switches.  Normally you try to create physical configurations that support your logical QoS scheme.

With your router and switch, your ingress policy and classes might be almost identical.  Egress, though, it going to be much different.