Cisco NME-X-23ES-1G User Guide - Page 108

Configuration Tasks 16- and 36-Port Ethernet Switch Module for Cisco 2600 Series, Cisco 3600 Series, and Cisco 3700 Series Step 4 Step 5 Command Router(config)# switchport access vlan vlan-id Router(config)# switchport voice vlan vlan-id Purpose Configures the port as "access" and assigns a data VLAN. Configures the voice port with a VVID that will be used exclusively for voice traffic. Voice Traffic and VVID The Ethernet switch network module can automatically configure voice VLAN. This capability overcomes the management complexity of overlaying a voice topology onto a data network while maintaining the quality of voice traffic. With the automatically configured voice VLAN feature, network administrators can segment phones into separate logical networks, even though the data and voice infrastructure is physically the same. The voice VLAN feature places the phones into their own VLANs without the need for end-user intervention. A user can plug the phone into the switch, and the switch provides the phone with the necessary VLAN information. Configuring a Single Subnet for Voice and Data For network designs with incremental IP telephony deployment, network managers can configure the Ethernet switch network module so that the voice and data traffic coexist on the same subnet. This might be necessary when it is impractical either to allocate an additional IP subnet for IP phones or to divide the existing IP address space into an additional subnet at the remote branch, it might be necessary to use a single IP address space for branch offices. (This is one of the simpler ways to deploy IP telephony.) When this is the case, you must still prioritize voice above data at both Layer 2 and Layer 3. Layer 3 classification is already handled because the phone sets the Type of Service (ToS) bits in all media streams to an IP Precedence value of 5. (With Cisco CallManager Release 3.0(5), this marking changed to a Differentiated Services Code Point ([DSCP]) value of EF.) However, to ensure that there is Layer 2 classification for admission to the multiple queues in the branch office switches, the phone must also use the User Priority bits in the Layer 2 802.1p header to provide Class of Service (CoS) marking. Setting the bits to provide marking can be done by having the switch look for 802.1p headers on the native VLAN. This configuration approach must address two key considerations: • Network managers should ensure that existing subnets have enough available IP addresses for the new Cisco IP phones, each of which requires a unique IP address. • Administering a network with a mix of IP phones and workstations on the same subnet might pose a challenge. To automatically configure Cisco IP phones to send voice and data traffic on the same VLAN, use the following commands beginning in privileged EXEC mode: Step 1 Step 2 Command Router# configure terminal Router(config)# interface interface Purpose Enters global configuration mode. Enters the interface configuration mode and the port to be configured (e.g., interface fa5/1). 108 Cisco IOS Release 12.2(2)XT, 12.2(8)T, and 12.2(15)ZJ