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Voice over Wireless LAN Solution Guide v1.0 December 2005
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Page 45
An ERS 5510/5520 connected to the WTM 2245 at Interface C can be configured to simply trust
the markings set by the WTM 2245. Also, you would set WTM 2245 to mark traffic with a DSCP
value of 0x2e.
2.5.3.4 Prioritizing/marking native VoIP traffic
As noted previously, it is assumed that remote VoIP telephones, call servers, and LAN switching
equipment are properly marking and classifying traffic. Locally, as the VoIP packets leave the
WTM 2245, they will be classified properly if the ERS 5510/5520 is set to trust markings.
2.5.4 Ethernet Routing Switch 8300/8600
To keep redundant material to a minimum, the descriptions from the corresponding ES family
sections will not be repeated. Only where the ERS 8300/8600 differs in capabilities or
recommendations from the ES will further discussion be added. An ERS 8300/8600 may be
located at a number of positions in the network with respect to the WLAN products, as shown in
Figure 18.
Figure 18: ERS 8300/8600 performing packet classification
When another device, such as an ES or ERS 5500 series, is directly connected to one of these
WLAN or VoIP components and the ERS 8300/8600 are core devices in the DiffServ domain, the
ES performs the classification and marking of traffic. If that is the case, then the proper
configuration of an ERS 8300/8600 as a DiffServ core device is to simply respect the PHB
specified by the DSCP value of the packet as marked by the DiffServ edge device. It is assumed,
however, that in the descriptions that follow the ERS 8300/8600 is directly connected to these
WLAN and VoIP devices and cannot rely on packets being premarked. This is strictly for the sake
of discussion concerning the capabilities of the ERS 8300/8600 given possible locations within
various networks. Because the ERS 8300 has PoE ports, and the ERS 8600 does not, only an
ERS 8300 can provide Interface A to AP 2330s. Given a particular real world network, implement
the recommendations below if the ERS 8300/8600 provides any of the shown interfaces to the
WLAN and telephony devices. If the ERS 8300/8600 is a core DiffServ device, implement DSCP-
based filters to respect the markings.
2.5.4.1 Prioritizing/marking CAPP
For an ERS 8300/8600 providing Interface B to a WSS 2300, you can use a prioritization
approach similar to that used for the ES family products. That is specifically to have the WSS
2300 mark all voice and data traffic, leaving only the control traffic unmarked. A DiffServ access
port on the ERS 8600/8300 together with filters can therefore be used to re-mark DSCP values of