How to Create Map Rules for RTP Traffic

You can use GigaVUE‑OS to set map rules matching even or odd port numbers to focus on different aspects of VoIP traffic.

VoIP implementations typically send RTP on even port numbers and RTCP on the next available odd port number. The following example constructs a map on network ports 1/4/x7 and 1/4/x2 with map rules designed to block RTP on the even-numbered ports in its common ranges.

Table 1: Blocking RTP Traffic on Common Ports
Command	Description
(config) # map alias no_rtp	Enters the map prefix mode for a new map with the alias of no_rtp.
(config map alias no_rtp) # type regular byRule	Specifies the map type and subtype.
(config map alias no_rtp) # from 1/4/x1..x2	Applies the map to traffic arriving on network ports 1/4/x1 and 1/4/x2.
to 1/5/x12	Sends matching traffic to tool port 1/5/x12
rule add drop portsrc 5004	Constructs a rule to drop traffic with a source port of 5004.
rule add drop portdst 5004	Constructs a rule to drop traffic with a destination port of 5004.
rule add drop portsrc 16384..16624 portsrc-subset even	Constructs a rule to drop traffic with an even-numbered source port in the range of 16384..16624. This is a standard RTP port range used by Cisco equipment.
rule add drop portdst 16384..16624 portdst-subset even	Constructs a rule to drop traffic with an even-numbered source port in the range of 16384..16624.
shared-collector 1/5/x8	Sends non-matching traffic to a shared-collector on 1/5/x8. This shared-collector will be used for packets not matching any maps on network ports 1/4/x1..x2; refer to the “About Shared Collectors” section in the GigaVUE Fabric Management Guide for details.
(config map alias no_rtp) # exit	Exits the map prefix mode.
(config) # write memory	Saves changes to the active configuration file.

Use the show map brief and show map command output to check the progress.