/mcpQuality of Service for Voice over IP Resource Reservation Protocol 31 QoSVoIP.mif priority queue, which might affect the quality of existing voice calls and the performance of the traffic using the WFQ system. You need to take the effects of bursty or noncritical traffic into account when you are defining a custom priority queue profile. You should understand all the implications on other types of traffic—in particular, when the PQ profile could let flows with some degree of burstiness into the priority queue. RSVP support for LLQ prioritizes voice packets but it does not take care of the voice signaling. It may not be possible to initiate new calls during periods of heavy congestion due to loss of signaling packets. To address this situation, you can reserve some amount of bandwidth explicitly for signaling packets using the MQC. You can also mark RSVP messages for special treatment using the ip rsvp signaling dscp interface configuration command. In the following configuration example, voice packets are prioritized using RSVP; and the signaling is guaranteed a minimum bandwidth during periods of congestion through the MQC: Configuration Example 14: RSVP Support for LLQ + QoS for Signaling Traffic hostname LongBay ! class-map h323 match access-group 101 ! policy-map VOIP_SIG class h323 set ip dscp 34 bandwidth 96 class class-default fair-queue ! isdn switch-type primary-ni call rsvp-sync ! controller T1 1/0 framing esf linecode b8zs pri-group timeslots 1-24 ! interface Ethernet0/0 ip address 10.0.152.254 255.255.255.0 ! interface Serial0/0 bandwidth 1536 ip address 10.10.1.1 255.255.255.0 encapsulation ppp ip tcp header-compression iphc-format ip rtp header-compression iphc-format service-policy output VOIP_SIG ip rsvp bandwidth 1152 24 ! interface Serial1/0:23 no ip address no logging event link-status isdn switch-type primary-ni isdn incoming-voice voice no cdp enable ! access-list 101 permit tcp any eq 1720 any access-list 101 permit tcp any any eq 1720 ! voice-port 1/0:23 !