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Community Member

How would I limit email with Qos?

i want to test the effect of limiting our email (exchange) traffic to a certain amount of bandwidth to allow for a better flow of voip traffic. i currently have qos in place but i still have some voice issues . i know our qos policy is working but i need to tone down email. i think it's b/c we pass a ton of email traffic through 3 t-1's along with voice traffic.

so i was thinking of creating an acl for email then giving it some where around 300 - 500 k per t-1 and adding it to the current qos config.

class-map match-all voice-signaling

match ip dscp af31

class-map match-any voice-traffic

match ip dscp ef

match ip rtp 16384 16383

!

!

policy-map EWT_SP

class voice-traffic

priority 800

class voice-signaling

bandwidth 8

class class-default

fair-queue

sh policy-map EWT_SP

Policy Map EWT_SP

Class voice-traffic

Strict Priority

Bandwidth 1042 (kbps) Burst 26050 (Bytes)

Class voice-signaling

Bandwidth 8 (kbps) Max Threshold 64 (packets)

Class class-default

Flow based Fair Queueing

Bandwidth 0 (kbps) Max Threshold 64 (packets)

EWT_NOC#sh policy-map int ser4/0:0

Serial4/0:0

Service-policy output: EWT_SP

Class-map: voice-traffic (match-any)

2148676 packets, 136995992 bytes

30 second offered rate 0 bps, drop rate 0 bps

Match: ip dscp ef (46)

967403 packets, 61480518 bytes

30 second rate 0 bps

Match: ip rtp 16384 16383

1181273 packets, 75515474 bytes

30 second rate 0 bps

Queueing

Strict Priority

Output Queue: Conversation 264

Bandwidth 1042 (kbps) Burst 26050 (Bytes)

(pkts matched/bytes matched) 772408/19968407

(total drops/bytes drops) 0/0

Class-map: voice-signaling (match-all)

2604 packets, 320684 bytes

30 second offered rate 0 bps, drop rate 0 bps

Match: ip dscp af31 (26)

Queueing

Output Queue: Conversation 265

Bandwidth 8 (kbps) Max Threshold 64 (packets)

(pkts matched/bytes matched) 2604/320684

(depth/total drops/no-buffer drops) 0/0/0

Class-map: class-default (match-any)

70045641 packets, 16140010608 bytes

30 second offered rate 414000 bps, drop rate 8000 bps

Match: any

Queueing

Flow Based Fair Queueing

Maximum Number of Hashed Queues 256

(total queued/total drops/no-buffer drops) 25/21976/0

6 REPLIES
Super Bronze

Re: How would I limit email with Qos?

Depending on IOS version, you would define a class for you e-mail and activate a shaper or policier.

PS:

Seeing

30 second offered rate 414000 bps, drop rate 8000 bps

and

(total queued/total drops/no-buffer drops) 25/21976/0

while other class rate show zero rates, how much bandwidth is available on this link?

If the link's full bandwidth is small enough, your solution might be via LFI.

Community Member

Re: How would I limit email with Qos?

while other class rate show zero rates, how much bandwidth is available on this link? this is a HDLC t-1.

If the link's full bandwidth is small enough, your solution might be via LFI. the circuit is a full t-1.

i'll look into shaping.

thanks.

Super Bronze

Re: How would I limit email with Qos?

Ok, for a full T-1, you shouldn't need LFI.

Unless you didn't post parts of your outbound policy stats, the stats seem off for a full T. Have you seen the interface's stats hit about 1.5 Mbps?

Community Member

Re: How would I limit email with Qos?

if you mean do the ser int peak at nearly 100% - yes it can some times. i included the " sh policy-map int ser4/0:0" and sh in ser4/0:0.

EWT_NOC#sh policy-map int ser4/0:0

Serial4/0:0

Service-policy output: EWT_SP

Class-map: voice-traffic (match-any)

2242510 packets, 142964898 bytes

30 second offered rate 0 bps, drop rate 0 bps

Match: ip dscp ef (46)

981198 packets, 62335478 bytes

30 second rate 0 bps

Match: ip rtp 16384 16383

1261312 packets, 80629420 bytes

30 second rate 0 bps

Queueing

Strict Priority

Output Queue: Conversation 264

Bandwidth 1042 (kbps) Burst 26050 (Bytes)

(pkts matched/bytes matched) 812584/21020804

(total drops/bytes drops) 0/0

Class-map: voice-signaling (match-all)

2734 packets, 336920 bytes

30 second offered rate 0 bps, drop rate 0 bps

Match: ip dscp af31 (26)

Queueing

Output Queue: Conversation 265

Bandwidth 8 (kbps) Max Threshold 64 (packets)

(pkts matched/bytes matched) 2734/336920

(depth/total drops/no-buffer drops) 0/0/0

Class-map: class-default (match-any)

79607911 packets, 25344098513 bytes

30 second offered rate 1244000 bps, drop rate 0 bps

Match: any

Queueing

Flow Based Fair Queueing

Maximum Number of Hashed Queues 256

(total queued/total drops/no-buffer drops) 0/22405/0

EWT_NOC#sh int ser4/0:0

Serial4/0:0 is up, line protocol is up

Hardware is DSCC4 Serial

Description: Second T1 to 7204 on Channel 11

Interface is unnumbered. Using address of FastEthernet0/0.10 (172.16.1.1)

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,

reliability 255/255, txload 117/255, rxload 13/255

Encapsulation HDLC, loopback not set

Keepalive set (10 sec)

Last input 00:00:03, output 00:00:00, output hang never

Last clearing of "show interface" counters never

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 22405

Queueing strategy: Class-based queueing

Output queue: 13/1000/64/22405 (size/max total/threshold/drops)

Conversations 2/66/256 (active/max active/max total)

Reserved Conversations 1/1 (allocated/max allocated)

Available Bandwidth 108 kilobits/sec

30 second input rate 81000 bits/sec, 73 packets/sec

30 second output rate 709000 bits/sec, 109 packets/sec

33191015 packets input, 2102745354 bytes, 0 no buffer

Received 64818 broadcasts, 0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

81839207 packets output, 3906379027 bytes, 0 underruns

0 output errors, 0 collisions, 5 interface resets

0 output buffer failures, 0 output buffers swapped out

1 carrier transitions

Timeslot(s) Used:1-24, SCC: 0, Transmitter delay is 0 flags

Super Bronze

Re: How would I limit email with Qos?

Other than the interface showing "30 second output rate 709000 bits/sec" and the policy showing "30 second offered rate 1244000 bps, drop rate 0 bps", these don't show drops at 400 Kbps.

For a fast test, to see whether shaping or policing provides the benefit you seek, you could try the shaping or policing in the default class.

Community Member

Re: How would I limit email with Qos?

thanks i'll look into shaping.

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