Unable to get VoIP QoS working on PIX

Mar 27, 2007 2 Replies

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mhoppes 19 years ago

I am attempting to get VoIP QoS running on a Cisco PIX. It's not working.

Running 7.0(1) It is a PIX-515

Config: interface Ethernet0 nameif outside security-level 0 ip address xxx.xxx.xxx.98 255.255.255.224 !

access-list 109 extended permit udp any any eq 4569

class-map VOIP match access-list 109 (also tried) match port udp eq 4569 ! policy-map VOIP class VOIP priority ! service-policy VOIP interface outside

Any ideas as to why this is not working? access-list 109; 1 elements access-list 109 line 1 extended permit udp any any eq 4569 (hitcnt=0)

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headsetadapter.com 19 years ago

Why are you trying to match the only one UDP Port (4569)? UDP Port 4569 is used by IAX2 protocol between two Asterisk boxes, and usually it does not require QoS. However you need QoS for RTP traffic, which uses dynamic UDP ports in the range >15000 (in case you use a standard Asterisk configuration), and ports above 16356 in case of Cisco IP Phones. So, it would be better if you either specify other access-list, or use another parameter for selecting traffic (for example, use DSCP value). Here is a Cisco example, how to configure QoS over VPN on PIX 7.x code:

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Mike CCNP, CCDP, CCSP, Cisco Voice, MCSE W2K, MCSE+I, Security+, Sun SCSA, Checkpoint CCSA, etc. CCIE R&S (in progress), CCIE Voice (in progress)

------ Headset Adapters for Cisco IP Phones

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mhoppes 19 years ago

You are correct, it is IAX. The reason we are trying to QoS the IAX2 traffic is because there is a single T1 line. Often the T1 will become saturated. When this happens, VoIP call quality (over IAX) breaks up. We are trying to assure that the VoIP calls have priority over data traffic.

Do you have a better solution.

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