Question

QoS - SCCP vs. SIP

Asked by: fcnetimg

I have a Cisco CME running SCCP with a few phones located across an Internet L2L VPN.  The Internet router at the main site is an 1841 with a high bandwidth cable connection.  I have successfully implemettned QoS on this router to mark and class outbound VoIP while policing inbound ftp/http.  The remote phones work well with the CME system.

I implemented a Switchvox system at the main office which uses SIP for call control.  I applied the same style QoS policies to that traffic as that of the CME.  File downloads interfere with outbound audio to the remote site on the SIP system while simultaneous calls on the CME SCCP system to the remote site are perfect.

I'm having difficulty determining why the SIP based and SCCP based systems react differently under the same circumstances.  In theory, the RTP streams function similarly, while the call control is different.  Any opinions or advise would be appreciated.

This Question has been solved and asker verified All Experts Exchange premium technology solutions are available to subscription members.

Subscribe now for full access to Experts Exchange and get

Instant Access to this Solution

  • Plus...
  • 30 Day FREE access, no risk, no obligation
  • Collaborate with the world's top tech experts
  • Unlimited access to our exclusive solution database
  • Never be left without tech help again

Subscribe Now

Asked On
2009-05-22 at 15:15:44ID24432534
Tags

QoS

,

VoIP

,

SCCP

,

SIP

,

CME

Topics

Voice Over IP

,

IP Telephony

,

IP PBX Systems

Participating Experts
2
Points
0
Comments
10

Trusted by hundreds of thousands everyday for fast, accurate and reliable tech support.

  • "The time we save is the biggest benefit of Experts Exchange to Warner Bros. What could take multiple guys 2 hours or more each to find is accessed in around 15 minutes on Experts Exchange." Mike Kapnisakis, Warner Bros.
  • "Our team likes having a resource that is more secure than just using Google and most experts using this service really know their stuff. It's nice to look here first versus using Google." Dayna Sellner, Lockheed Martin
  • "Anytime that I've been stumped with a problem, 9 out of 10 times Experts Exchange has either the accepted solution or an open discussion of the potential solution to the problem." Kenny Red, eBay Inc.

See what Experts Exchange can do for you.

Got a question?

We've got the answer.

Experts Exchange has been collecting answers to technology questions since 1996…3 million and counting! If you have a question, chances are we already have your answer.

Screenshot of Experts Exchange Knowledgebase

Need individual assistance?

Our experts are ready to help.

If you can't find the exact answer you're looking for, ask our exclusive community of 50,000 experts. You’ll get a personalized answer from a trusted professional.

Screenshot of Experts Exchange Knowledgebase

Want to learn from the best?

Read articles from industry experts.

Thousands of free tech tips, tricks, how-to’s and tutorials are available in our peer reviewed articles section. See for yourself how smart our experts are, no login required.

Screenshot of an Article

Working on a long term project?

Store your work and research.

Save solutions to your questions, answers you’ve discovered through searching plus helpful articles in your personal knowledgebase for easy future access.

Screenshot of Experts Exchange Knowledgebase

Access the answers to your technology questions today.

Subscribe Now

30-day free trial. Register in 60 seconds.

What Makes Experts Exchange Unique?

Members of the expert community talk about why the experience at Experts Exchange is different than what you will find anywhere else.

Trusted by the world's most respected brands.

image of each brand's logo

Faithfully serving IT professionals since 1996.

Experts Exchange Logo

Try it out and discover for yourself.

Subscribe Now

30-day free trial. Register in 60 seconds.

Related Solutions

  1. help with VOIP, SIP
    I am currently looking into using VOIP in our organisation. Ive been reading up and need some suggestions. One of the main things we need in multi-party confrencing. We would like to be able to do is make calls to people on pbx from sip/voip, we would actually like to go comp...
  2. QoS for VoIP
    What is a good way to set up QoS for VoIP? Of course, this question is a catch 22 since it really depends what device you're using. But I'd like to look past that and first ask what the best way to set up QoS is. Is it better to have the QoS implemented as: Port Based Protoc...
  3. Adtran QoS
    I have a adtran 1335. I was wondering if my QoS looks to be setup properly for VOIP. The phones are Polycom with a CoS of 5. The dscp on this phone is 40. We have a T1 for the wan and have SIP trunks from bandwidth.com. Attached is the config. Some information has been remove...
  4. qos and msn
    I've applied QOS on a site that has cisco routers 877-M series ... QOS defines 6 to 7 classes that have commands of bandwidth percent and set dscp values each ..... after applying the qos on the interface atm 0.1 and dialer interface, everything works fine but people cant log...

Free Tech Articles

  1. WARNING: 5 Reasons why you should NEVER fix a computer for free.
    It is in our nature to love the puzzle. We are obsessed. The lot of us. We love puzzles. We love the challenge. We thrive on finding the answer. We hate disarray. It bothers us deep in our soul. W...
  2. SCCM OSD Basic troubleshooting
    SCCM 2007 OSD is a fantastic way to deploy operating systems, however, like most things SCCM issues can sometimes be difficult to resolve due to the sheer volume of logs to sift through and the dispe...
  3. Migrate Small Business Server 2003 to Exchange 2010 and Windows 2008 R2
    This guide is intended to provide step by step instructions on how to migrate from Small Business Server 2003 to Windows 2008 R2 with Exchange 2010. For this migration to work you will need the fo...
  4. Create a Win7 Gadget
    This article shows you how to create a simple "Gadget" -- a sort of mini-application supported by Windows 7 and Vista. Gadgets can be dropped anywhere on the desktop to provide instant information, ...
  5. Outlook continually prompting for username and password
    There have been a lot of questions recently regarding Outlook prompting for a username and password whilst using Exchange 2007. There are a few reasons why this would happen and I will try to cover t...
  6. Backup Exchange 2010 Information Store using Windows Backup
    There seems to be quite a lot of confusion around the ability to backup Exchange 2010 using the built in Windows Backup feature. This stems from the omission of this feature prior to Exchange 2007 s...

Cloud Class Webinars

  1. Avoiding Bugs in Microsoft Access
    Alison Balter takes and in-depth look at avoiding bugs in Access. In this webinar you will learn about using the immediate window to debug your applications, invoking the debugger, using breakpoints to troubleshoot, stepping through code, setting the next statement to execute, ...
  2. Top 10 Best New Features in Visio 2010
    Scott Helmers gives live demonstrations of the top 10 new features in Visio 2010. This webinar will teach you how to create compelling diagrams by adding shapes to the page with a single click, linking the shapes in a diagram to data in Excel (or SQL Server, or SharePoint), ...
  3. IT Consultant Business Secrets Revealed
    Michael Munger, Experts Exchange tech pro and IT consultant, pulls back the curtain on his very successful businesses and answers question on every IT consultant and business owner should know about. He shares secrets on what he did to solve the 5 most common problems in IT, ...
  4. Disaster Recovery and Business Continuity
    Quest CTO, Mike Billon, gives an overview of the steps involved in building a dunamic disaster recovery plan. Through case studies and an examination of software/hardware tooles for monitoring and testing, you'll gain a better understandin of where you are, where you want ...
  5. Organize Your Visio Diagrams with Containers and Lists
    Scott Helmers uses cross functional flowcharts, wireframe diagrams, data graphic legends and seating charts to teach you: how to ustilize all three new structured diagram components in Visio 2010, the best practices for organizeing shapes in previous version of Visio, how to organize ...
  6. How to Us Objects, Properties, Events and Methods in Microsoft Access
    Alison Dalter gives an in-depbth look at objects, properties, events and methods in Microsoft Access. In this webinar you will learn about using the object browser, referring to objects, working with properties and methods, working with object variables, understanding the ...

Join the Community

Give a Little. Get a Lot.

Join the community of experts here and help other tech pros by answering question in your area of expertise. You can earn FREE access to all Experts Exchange's premium features and resources.

Join the Community

Answers

 

by: netbonesPosted on 2009-05-22 at 20:08:29ID: 24456563

Can you post your config for the SIP QoS?

 

by: fcnetimgPosted on 2009-05-23 at 12:12:08ID: 24459188

Sure.  The QoS settings apply to both the SCCP and SIP VoIP traffic.  As I said, the CME SCCP is flawless during file downloads while a simultaneous SwitchVox SIP call is severely chopped up.

The QoS portions of the config follow.  I look for any CS5 marked traffic or anything originating from the SwitchVox server (10.0.0.16) or the SIP phone (10.0.0.121) and remark it as EF as it goes out through the LAN interface.  The WAN interface policy looks for anything going out marked EF and puts it iin the priority queue.  At the same time, the WAN interface polices FTP/HTTP inbound to reserve bandwidth for voice.

class-map match-any FTP-Traffic
 match protocol ftp
 match protocol http
 match protocol secure-http
 match protocol secure-ftp
class-map match-any CS5
 match ip dscp cs5
 match access-group name switchvox-server
 match access-group name switchvox-phone
class-map match-any VOICE
 match ip dscp ef
class-map match-any Signaling
 match ip dscp cs3
 match ip dscp af31
class-map match-any INTERNETWORK-CONTROL
 match ip dscp cs6
 match access-group name IKE
class-map match-any TRANSACTIONAL-DATA
 match ip dscp af21  af22
policy-map Limit-FTP
 class FTP-Traffic
   police cir 16000000
     conform-action transmit
     exceed-action drop
policy-map MARKING
 class CS5
  set dscp ef
policy-map V3PN-EDGE
 class VOICE
    priority percent 33
 class INTERNETWORK-CONTROL
    bandwidth percent 5
 class TRANSACTIONAL-DATA
    bandwidth percent 21
    queue-limit 20 packets
 class SCAVENGER
    bandwidth percent 1
    queue-limit 1 packets
 class Signaling
    bandwidth percent 5
 class class-default
    fair-queue
     random-detect
interface FastEthernet0/0
 description connected to Private LAN
 ip address 10.0.0.1 255.255.255.0
 ip nat inside
 ip virtual-reassembly
 zone-member security ZN-Inside_LAN
 ip tcp adjust-mss 1300
 duplex auto
 speed auto
 service-policy input MARKING
interface FastEthernet0/1
 description Cable modem
 bandwidth 2200
 ip address w.x.y.z 255.255.255.240
 ip nat outside
 ip virtual-reassembly
 zone-member security ZN-Outside_T1
 duplex auto
 speed auto
 crypto map combinedmap
 service-policy input Limit-FTP
 service-policy output V3PN-EDGE
ip access-list extended switchvox-phone
 permit ip host 10.0.0.121 any
ip access-list extended switchvox-server
 permit ip host 10.0.0.16 any

 

by: table9Posted on 2009-05-23 at 16:43:26ID: 24459947

The first thing I would do is make sure you are getting matches on the acls when you make a call.  Next I would get a trace and look at the packets and make sure they are being marked appropriately with dscp on the far end.  Then post the results.  

 

by: table9Posted on 2009-05-23 at 16:45:40ID: 24459950

 

by: fcnetimgPosted on 2009-05-26 at 06:40:20ID: 24473122

Here are some counters that demonstrate packets are being marked and evaluated by the routers.  

Local#sh  policy-map interface
 FastEthernet0/0

  Service-policy input: MARKING

    Class-map: CS5 (match-any)
      4345 packets, 978661 bytes
      5 minute offered rate 34000 bps, drop rate 0 bps
      Match: ip dscp cs5 (40)
        0 packets, 0 bytes
        5 minute rate 0 bps
      Match: access-group name switchvox-server
        4345 packets, 978661 bytes
        5 minute rate 34000 bps
      QoS Set
        dscp ef
          Packets marked 4345

    Class-map: class-default (match-any)
      32415 packets, 2768899 bytes
      5 minute offered rate 166000 bps, drop rate 0 bps
      Match: any
 FastEthernet0/1

  Service-policy input: Limit-FTP

    Class-map: FTP-Traffic (match-any)
      69885 packets, 90475434 bytes
      5 minute offered rate 3979000 bps, drop rate 0 bps
      Match: protocol ftp
        0 packets, 0 bytes
        5 minute rate 0 bps
      Match: protocol http
        69136 packets, 89962823 bytes
        5 minute rate 3952000 bps
      Match: protocol secure-http
        749 packets, 512611 bytes
        5 minute rate 11000 bps
      Match: protocol secure-ftp
        0 packets, 0 bytes
        5 minute rate 0 bps
      police:
          cir 16000000 bps, bc 500000 bytes
        conformed 69885 packets, 90475434 bytes; actions:
          transmit
        exceeded 0 packets, 0 bytes; actions:
          drop
        conformed 10391000 bps, exceed 0 bps

    Class-map: class-default (match-any)
      7168 packets, 1548510 bytes
      5 minute offered rate 62000 bps, drop rate 0 bps
      Match: any

  Service-policy output: V3PN-EDGE

    queue stats for all priority classes:
      Queueing
      queue limit 64 packets
      (queue depth/total drops/no-buffer drops) 0/0/0
      (pkts output/bytes output) 4628/1297104

    Class-map: VOICE (match-any)
      4628 packets, 1038927 bytes
      5 minute offered rate 38000 bps, drop rate 0 bps
      Match: ip dscp ef (46)
        4628 packets, 1038927 bytes
        5 minute rate 38000 bps
      Priority: 33% (726 kbps), burst bytes 18150, b/w exceed drops: 0


    Class-map: INTERNETWORK-CONTROL (match-any)
      23 packets, 2116 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: ip dscp cs6 (48)
        23 packets, 2116 bytes
        5 minute rate 0 bps
      Match: access-group name IKE
        0 packets, 0 bytes
        5 minute rate 0 bps
      Queueing
      queue limit 64 packets
      (queue depth/total drops/no-buffer drops) 0/0/0
      (pkts output/bytes output) 23/3082
      bandwidth 5% (110 kbps)

    Class-map: TRANSACTIONAL-DATA (match-any)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: ip dscp af21 (18) af22 (20)
        0 packets, 0 bytes
        5 minute rate 0 bps
      Queueing
      queue limit 20 packets
      (queue depth/total drops/no-buffer drops) 0/0/0
      (pkts output/bytes output) 0/0
      bandwidth 21% (462 kbps)

    Class-map: SCAVENGER (match-all)
      2 packets, 330 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: ip dscp cs1 (8)
      Queueing
      queue limit 1 packets
      (queue depth/total drops/no-buffer drops) 0/0/0
      (pkts output/bytes output) 2/120
      bandwidth 1% (22 kbps)

    Class-map: Signaling (match-any)
      83 packets, 6336 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: ip dscp cs3 (24)
        83 packets, 6336 bytes
        5 minute rate 0 bps
      Match: ip dscp af31 (26)
        0 packets, 0 bytes
        5 minute rate 0 bps
      Queueing
      queue limit 64 packets
      (queue depth/total drops/no-buffer drops) 0/0/0
      (pkts output/bytes output) 83/10802
      bandwidth 5% (110 kbps)

    Class-map: class-default (match-any)
      35547 packets, 2759527 bytes
      5 minute offered rate 158000 bps, drop rate 0 bps
      Match: any
      Queueing
      queue limit 64 packets
      (queue depth/total drops/no-buffer drops/flowdrops) 0/0/0/0
      (pkts output/bytes output) 35542/2955648
      Fair-queue: per-flow queue limit 16
        Exp-weight-constant: 9 (1/512)
        Mean queue depth: 0 packets
        class     Transmitted       Random drop      Tail/Flow drop Minimum Maximum Mark
                  pkts/bytes    pkts/bytes       pkts/bytes    thresh  thresh  prob

        0           43127/3989545         0/0              0/0                 20            40  1/10
        1               0/0               0/0              0/0                 22            40  1/10
        2               0/0               0/0              0/0                 24            40  1/10
        3               0/0               0/0              0/0                 26            40  1/10
        4               0/0               0/0              0/0                 28            40  1/10
        5               0/0               0/0              0/0                 30            40  1/10
        6               0/0               0/0              0/0                 32            40  1/10
        7               0/0               0/0              0/0                 34            40  1/10
 

 

by: table9Posted on 2009-05-26 at 08:20:40ID: 24474170

I do not see the sip marking in the config.  I may be missing it though.
class-map match-any sip
match ip dscp cs3
match protocol sip

 

by: fcnetimgPosted on 2009-05-26 at 08:32:27ID: 24474283

As part of my troubleshooting, I'm taking all IP from the server and marking it EF.  The log I posted proved to me that the voice packet were seen by the VOICE class map on both sides.

class-map match-any CS5
 match access-group name switchvox-server
policy-map MARKING
 class CS5
  set dscp ef

 

by: table9Posted on 2009-05-26 at 10:27:24ID: 24475440

When troubleshooting something like this with qos be as specific as possible.  I would remove the acl and specifically mark the sip traffic.  As a note sip will use tcp or udp depending on the application.  

 

by: fcnetimgPosted on 2009-05-28 at 08:18:20ID: 24494219

It turns out that there was nothing wrong with my qos config (or any of its iterations throughout the troubleshooting process).  The problem was that the 1841 router processor was over-utilized.  Running IPSec VPN, SSL VPN, QoS, Zone-based firewall with NAT, content filtering, IPSLA for failover while processing downloads at 25Mbps from a broadband connection was too much for the device to handle.  I'm surprised at the result, since the device is marketed to handle all of these functions.  Even TAC concurs that this is the issue.

The initial question still remains however--why is the Cisco CME/SCCP system so much more resilient to poor bandwidth conditions than the SIP based SwitchVox system.  Since no one really commented on that and I have some closure on the SIP issue being related to router performance, I will go ahead and close this.

 

by: table9Posted on 2009-05-28 at 08:38:13ID: 24494453

The short answer is that a greater amount of development has gone into sccp.  

20120131-EE-VQP-002

3 Ways to Join

30-Day Free Trial

The Experts

98% positive feedback on 31,087 answers since March 2000. angeliii is a Microsoft Most Valuable Professional for his work with MS SQL Server & Develoment.

He has also proven his knowledge of Visual Basic Programming, PHP Scripting and Oracle Databases.

The Experts

97% positive feedback on 10,752 answers since July 2000. lrmoore has more than 18 years experience in the networking industry.

The six-time Mircosoft MVPs specialties include firewalls, virtual private networking, and network management.

Testimonials

"...and excellent source for support... Kind of like having your very own IT dept." Electriciansnet

Testimonials

"I was apprehensive at signing up at first. However... it has already made my life as an IT administrator much easier." JaCrews

Testimonials

"WOW! You guys have great, active, and knowledgeable people on here." moore50

Business Clients

Business Clients

In the Press

"If you’ve got a question... Experts Exchange can supply an answer.”

In the Press

"...an invaluable aid for both IT professionals and those who require tech support."

In the Press

"where IT professionals provide quick answers on just about any topic"

Business Account Plans

Loading Advertisement...