Guidelines For Using Voice On The Mesh Network - Cisco Mesh Access Points Deployment Manual

Cisco mesh access points, design and deployment guide, release 7.3

Table of Contents

Configuring Voice Parameters in Indoor Mesh Networks

All wired client traffic is restricted to a maximum 802.1p UP value of 5, except DHCP/DNS and ARP packets,

which go through the platinum queue.

The non-WMM wireless client traffic gets the default QoS priority of its WLAN. The WMM wireless client

traffic may have a maximum 802.11e value of 6, but it must be below the QoS profile configured for its

WLAN. If admission control is configured, WMM clients must use TSPEC signaling and get admitted by

CAC.

The CAPWAPP data traffic carries wireless client traffic and has the same priority and treatment as wireless

client traffic.

Now that the DSCP value is determined, the rules described earlier for the backhaul path from the RAP to

the MAP are used to further determine the backhaul queue on which the frame is transmitted. Frames transmitted

from the RAP to the controller are not tagged. The outer DSCP values are left intact, as they were first

constructed.

Bridging Backhaul Packets

Bridging services are treated a little differently from regular controller-based services. There is no outer DSCP

value in bridging packets because they are not CAPWAP encapsulated. Therefore, the DSCP value in the IP

header as it was received by the mesh access point is used to index into the table as described in the path from

the mesh access point to the mesh access point (backhaul).

Bridging Packets from and to a LAN

Packets received from a station on a LAN are not modified in any way. There is no override value for the

LAN priority. Therefore, the LAN must be properly secured in bridging mode. The only protection offered

to the mesh backhaul is that non-CAPWAP control frames that map to the platinum queue are demoted to the

gold queue.

Packets are transmitted to the LAN precisely as they are received on the Ethernet ingress at entry to the mesh.

The only way to integrate QoS between Ethernet ports on AP1500 and 802.11a is by tagging Ethernet packets

with DSCP. AP1500s take the Ethernet packet with DSCP and places it in the appropriate 802.11e queue.

AP1500s do not tag DSCP itself:

• On the ingress port, the AP1500 sees a DSCP tag, encapsulates the Ethernet frame, and applies the

corresponding 802.11e priority.

• On the egress port, the AP1500 decapsulates the Ethernet frame, and places it on the wire with an

untouched DSCP field.

Ethernet devices, such as video cameras, should have the capability to mark the bits with DSCP value to take

advantage of QoS.

QoS only is relevant when there is congestion on the network.

Note