QoS on Cisco 1720 router/2900xl switch

I am uncertain if I could use a hardware or software upgrade, but I have had trouble trying to implement any workable quality of service for VoIP traffic through my Cisco gear. I am not a Cisco/Networking kind of guy and many of the examples I found on the Cisco site seemed to use commands and options that I do not seem to have available. After performing a password recovery on the switch, I was finally able to implement a class of service (CoS) priority on a particular port on the switch that was plugged into our proprietary VoIP ATA board. All of our outgoing voice traffic goes through this port. I notice a general improvement most of the time, but occasionally the voice gets choppy and it appears to be that the port and/or the assigned protocol for that port keeps going down. Here is a excerpt from the hyperterm:

00:45:42: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to down
00:45:43: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, changed state to down
00:45:44: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to up
00:45:45: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, changed state to up

Here is the way I tried to prioritize my VoIP traffic:

interface FastEthernet0/2
!
interface FastEthernet0/3
!
interface FastEthernet0/4
switchport priority default 5
!

Thanks to help I received from here, I was able to reconfigure my ip address, and my ping and telnet ability. Thanks again and I would appreciate any further assistance in configuring these Cisco devices to work properly.

Regards,
Bill

 

can i have the output of your show version command?

Also what is this VOIP ATA board that you are referring to? Is only voip traffic being passed on switchport 4 or data traffic as well. If data traffic is passing over this port then all traffic is tagged as important.

http://www.cisco.com/warp/public/473/139.html#q15

Here is a link that will further explain COS on your 2900XL

 

HERE is something else to think about!

Q. Do the Catalyst 2900 XL and 3500 XL series switches provide priority scheduling in the input/ingress port?

A. Catalyst 2900 XL and 3500 XL series switches do not provide any priority scheduling in the input side. However, they do provide priority scheduling in the output/egress port.

 

Configuring VoIP priority

There is ONLY voice traffic coming over port 4 of the switch, no data.

Here is the output of the show version command as you asked:



Switch#show version
Cisco Internetwork Operating System Software
IOS (tm) C2900XL Software (C2900XL-C3H2S-M), Version 12.0(5.2)XU, MAINTENANCE IN
TERIM SOFTWARE
Copyright (c) 1986-2000 by cisco Systems, Inc.
Compiled Mon 17-Jul-00 17:35 by ayounes
Image text-base: 0x00003000, data-base: 0x00301F3C

ROM: Bootstrap program is C2900XL boot loader

Switch uptime is 5 days, 22 hours, 59 minutes
System returned to ROM by power-on
System image file is "flash:c2900XL-c3h2s-mz-120.5.2-XU.bin"


cisco WS-C2924-XL (PowerPC403GA) processor (revision 0x11) with 8192K/1024K byte
s of memory.
Processor board ID FAB0440M1D4, with hardware revision 0x01
Last reset from power-on

Processor is running Enterprise Edition Software
Cluster command switch capable
Cluster member switch capable
24 FastEthernet/IEEE 802.3 interface(s)

32K bytes of flash-simulated non-volatile configuration memory.
Base ethernet MAC Address: 00:03:E3:82:B0:00
Motherboard assembly number: 73-3382-08
Power supply part number: 34-0834-01
Motherboard serial number: FAB0439341L
Power supply serial number: PHI04130242
Model revision number: A0
Motherboard revision number: C0
Model number: WS-C2924-XL-EN
System serial number: FAB0440M1D4
Configuration register is 0xF

Switch#

I would like to know most of all what might be causing that port to keep going down and coming back up. Any ideas? I think this is the reason the voice gets choppy at times. Sometimes it goes down and gets reset many many times in a row.

 

have you done a show log? This command will allow you to see what logs are being kept and if there is anything happening before your port shuts. Also is the NIC on your voip ATA board functioning properly? if you do a ping from a windows terminal with a -t option do you lose packets?

 

Yikes

Well, here is the results of show log:



Switch#show log
Syslog logging: enabled (0 messages dropped, 0 flushes, 0 overruns)
Console logging: level debugging, 86 messages logged
Monitor logging: level debugging, 0 messages logged
Buffer logging: level debugging, 86 messages logged
File logging: disabled
Trap logging: level informational, 90 message lines logged

Log Buffer (4096 bytes):
rnet0/4, changed state to down
00:34:43: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, chang
ed state to down
00:34:43: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to up
00:34:44: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, chang
ed state to up
00:44:59: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to down
00:45:00: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, chang
ed state to down
00:45:01: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to up
00:45:02: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, chang
ed state to up
00:45:02: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to down
00:45:03: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, chang
ed state to down
00:45:04: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to up
00:45:05: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, chang
ed state to up
00:45:39: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to down
00:45:40: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, chang
ed state to down
00:45:41: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to up
00:45:42: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, chang
ed state to up
00:45:42: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to down
00:45:43: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, chang
ed state to down
00:45:44: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to up
00:45:45: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, chang
ed state to up
00:47:24: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to down
00:47:25: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, chang
ed state to down
00:47:26: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to up
00:47:27: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, chang
ed state to up
00:47:27: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to down
00:47:28: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, chang
ed state to down
00:47:29: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to up
00:47:30: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, chang
ed state to up
00:48:43: %LINK-4-ERROR: FastEthernet0/4 is experiencing errors
00:49:10: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to down
00:49:11: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, chang
ed state to down
00:49:11: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to up
00:49:12: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, chang
ed state to up
00:49:13: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to down
00:49:14: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, chang
ed state to down
00:49:14: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to up
00:49:15: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, chang
ed state to up
02:47:59: %LINK-4-ERROR: FastEthernet0/4 is experiencing errors
4d19h: %LINK-4-ERROR: FastEthernet0/4 is experiencing errors
5d02h: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to down
5d02h: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, changed
state to down
5d02h: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to up
5d02h: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, changed
state to up
5d02h: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to down
5d02h: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, changed
state to down
5d02h: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to up
5d02h: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, changed
state to up
5d19h: %SYS-5-CONFIG_I: Configured from console by console
5d20h: %SYS-5-CONFIG_I: Configured from console by console
5d20h: %SYS-5-CONFIG_I: Configured from console by console
5d20h: %SYS-5-CONFIG_I: Configured from console by console
Switch#

 

02:47:59: %LINK-4-ERROR: FastEthernet0/4 is experiencing errors
4d19h: %LINK-4-ERROR: FastEthernet0/4 is experiencing errors
5d02h: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to down


have you tried a different switchport?

 

proper config?

I am more than willing to try a different port, however port 4 didn't seem to have any problems until AFTER I enabled switchport with default priority, so I almost fear I will simply screw up another port. We are only using about 6 out of 24 though, so I have room to play.

Do you have any advice on all the configuring I should accomplish on the new port? Just switchport priority? Here is a show interface for the current port I am using (and is screwing up):




Switch#show interface FastEthernet0/4 switchport allowed-vlan
"NONE"
Switch#show interface FastEthernet0/4 switchport
Name: Fa0/4
Switchport: Enabled
Administrative mode: static access
Operational Mode: static access
Administrative Trunking Encapsulation: isl
Operational Trunking Encapsulation: isl
Negotiation of Trunking: Disabled
Access Mode VLAN: 1 (default)
Trunking Native Mode VLAN: 1 (default)
Trunking VLANs Enabled: NONE
Pruning VLANs Enabled: NONE

Priority for untagged frames: 5
Override vlan tag priority: FALSE
Voice VLAN: none
Appliance trust: none
Switch#

Please note that "Voice VLAN" says "none". Should this be different? Are the other settings correct?

Bill

 

The voice VLAN feature enables access ports to carry IP voice traffic from an IP phone. What exactly is hanging off of your switch on this port. I am thinking that you need to possibly make this a trunk port and enable dot1q trunking.

config t

int fa0/4
(first do a shut)shut
switchport mode trunk
switchport trunk encap dot1q
switchport priority default 5
spanning-tree portfast
(now bring it back up) no shut

 

We custom design and build our own VoIP ATA boards and the software is also ours. So we have a multi port ATA plugged into port 4 of the switch. Hence port 4 carries voice traffic only. Nothing else. I guess I don't understand totally what "trunking" is and how it relates to everything else. (you can take a peak at my next thread). I appreciate your help and you are about the only reason I am not climbing the clock tower with a sling shot as we speak.

 

Here is a good link on trunking

http://www.ciscopress.com/articles/article.asp?p=102157&seqNum=2&rl=1

There is always something new to learn in networking and i learn that every day

 

Huh?

I read it and it still didn't sink in entirely. Since our ATA is hooked directly to the switch which in turn it hooked directly to the router and then goes out to the rest of the world how is trunking going to be better than just giving the port a default priority? I'm sorry if I sound dense, but I don't understand how non-Cisco devices are going to interpret those header changes using Cisco trunking. I am willing to try it if you think it is worth my efforts. Should I only implement the trunking or the switchport priority as well, or do these not go well together?

 

Maybe im not understanding correctly. This is used for other people to talk over or a device used to talk out?

 

All outgoing phone calls from my company currently go through this ATA (VoIP) device. So there is voice coming and going like a regular phone except it is traveling over the Internet.

I implemented your last suggestion exactly as you outlined. I tested the phones and they do still work. I did not change ports, so I am still on port 4. Is there a way that I can clear the logs or do something so that I can be sure that I only see port/protocol crashes that occur from this time forward? Also is there any other screen output I can do so you can check the configuration to make sure it seems kosher? I am usually strictly software design and development so I am out of my area of expertise here. My boss just asked me to see if I could figure out a more robust configuration. I have other duties so this is only what I play with in between really important tasks.

 

Here is a screen capture of the current configuration:



Switch#show interface FastEthernet0/4 switchport allowed-vlan
"ALL"
Switch#show interface FastEthernet0/4 switchport
Name: Fa0/4
Switchport: Enabled
Administrative mode: trunk
Operational Mode: trunk
Administrative Trunking Encapsulation: dot1q
Operational Trunking Encapsulation: dot1q
Negotiation of Trunking: Disabled
Access Mode VLAN: 0 ((Inactive))
Trunking Native Mode VLAN: 1 (default)
Trunking VLANs Enabled: ALL
Trunking VLANs Active: 1,10
Pruning VLANs Enabled: 2-1001

Priority for untagged frames: 5
Override vlan tag priority: FALSE
Voice VLAN: none
Appliance trust: none
Switch#show running-config
Building configuration...

Current configuration:
!
version 12.0
no service pad
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname Switch
!
enable secret 5 $1$super$24dooper$$password!!1
enable password guessme
!
!
!
!
!
!
ip subnet-zero
!
!
!
interface FastEthernet0/1
!
interface FastEthernet0/2
!
interface FastEthernet0/3
!
interface FastEthernet0/4
duplex full
switchport trunk encapsulation dot1q
switchport mode trunk
switchport priority default 5
spanning-tree portfast
!
!
interface VLAN1
ip address xx.xx.xxx.xxx 255.255.255.240
no ip directed-broadcast
no ip route-cache
!
!
line con 0
transport input none
stopbits 1
line vty 0 4
password guessme
login
line vty 5 15
login
!
end

 

The voice vlan is used when u r making a port part of 2 vlans namely one data and other is a voice.

Please confirm whether any err disable has been configured on the switch. can u tell what connected on the other end of the switch.

if the other end is disabling the port this end here you can the link flapping.
Can you provide whats connected on the other end of the link.

Regards,

Srinath.M
:shake: