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Packet Marking

PureConnect products use Differentiated Services (DiffServ), and Class Selector PHB in some cases, to mark packets on an IP Network. RFC 2474 Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers describe these standards.

When possible, always mark packets at the source. PureConnect products allow marking of packets as they leave Interaction Media Server, telephones, and other PureConnect products. Configure all switches and routers that handle data and call flows to guarantee that the marked IP packets honor the QoS as they propagate though the network.

The endpoints QoS mark the RTP Packets (which use UDP) and SIP Packets (which through configuration can use UDP, TCP, or TLS). The QoS markings are in the 6-bit DSCP field of the ToS Byte of the IP header. The recommended (Default) value for RTP (voice) is 101110, which is EF / Expedited Forwarding. The recommended (Default) value for SIP Signaling is 011000, which is CS3 / Class Selector.

Source Endpoint Device Recommended Markings for RTP (voice) Recommended Markings for SIP (signaling) Configuration Location
SIP in CIC server NA SIP packets marked with 011000 (which is CS3 / Class Selector)

To alter this setting in Interaction Administrator, do the following steps:

  1. In the left pane, select the Lines object.

  2. In the right pane, double-click the Configuration item.

  3. In the Line Configuration dialog box, select the SIP Line Configuration tab.

  4. In the list box, click the Transport item.

  5. Scroll down to the SIP DSCP Value list box and select the value that you want to assign.
IC Notifier Notifier packets marked with 101110 (EF / Expedited Forwarding) To configure this setting in Interaction Administrator, do the following steps:

  1. In the left pane, select the Server Parameters object.

  2. In the right pane, right-click and then click New.

  3. In the Entry Name dialog box, type Switchover QOS DSCP and then click OK.

  4. In the Parameter Configuration - Switchover QOS DSCP dialog box, in the Parameter Value box, type 46 and then click OK.

  5. In the right pane, right-click and then click New.

  6. In the Entry Name dialog box, type Switchover Use QOS For Ping and then click OK.

  7. In the Parameter Configuration - Switchover Use QOS For Ping dialog box, in the Parameter Value box, type Yes and then click OK.
Interaction Media Server RTP packets marked with 101110 (which is EF / Expedited Forwarding) NA Interaction Media Server RTP is marked with EF. Interaction Media Server does not use SIP signaling. For more Information about marking on Interaction Media Server, see the Interaction Media Server Technical Reference.
AudioCodes Mediant Gateway RTP packets marked with 101110 (which is EF / Expedited Forwarding) SIP packets marked with 011000 (which is CS3 / Class Selector) The Mediant gateway defaults to DSCP value 101100 and marks packets by default. You can change this setting on the following page under Full Configuration\Network Settings\QoS Settings. Change the Default setting of 44 decimal (101000) for Control Premium QoS to 24 decimal (011000) for SIP signaling to use CS3.
Polycom Phones RTP packets marked with 101110 (which is EF / Expedited Forwarding) SIP packets marked with 011000 (which is CS3 / Class Selector) Configure manually with a sip.cfg file legacy Polycom telephones that the CIC server cannot provision. You can control provisioned phone markings in Interaction Administrator.
Interaction SIP Station RTP packets marked with 101110 (which is EF / Expedited Forwarding) SIP packets marked with 011000 (which is CS3 / Class Selector)

To alter this setting in Interaction Administrator, do the following steps:

  1. In the left pane, expand the server object.

  2. Expand the Stations object.

  3. Click the Default Station object

  4. In the right pane, double-click the Configuration item.

  5. In the Default Station Configuration dialog box, select the Global SIP Station tab.

  6. In the list box, select the Transport item.

  7. In the SIP DSCP Value list box, select the value that you want to assign to SIP packets.
SIP Soft Phone RTP packets marked with 101110 (which is EF / Expedited Forwarding) SIP packets marked with 011000 (which is CS3 / Class Selector) See the CIC Managed IP Phones Administrator's Guide.
Any soft phone for CIC RTP packets marked with 101110 (which is EF / Expedited Forwarding) SIP packets marked with 011000 (which is CS3 / Class Selector) See the CIC Managed IP Phones Administrator's Guide.

The following image displays an example of setting the SIP QoS in the Line Configuration that is available through Interaction Administrator. Ensure that you are consistent with any changes that you make and consider the SIP lines and stations that you use. To use DSCP, type18 in the SIP DSCP Value box to have it display 011000 (which is CS3) correctly. You don't need to restart Telephony Services. The next call from the server uses the new value.

Genesys highly recommends that you ensure the IP packets are getting marked correctly with the WireShark application, formerly known as Ethereal (http://www.wireshark.org). The following example displays the RTP header from a Polycom phone and the proper marking that applied:

It is not possible to mark the SIP Signaling coming from the CIC serve, except at the switch level with a service-policy. Let's assume that the CIC server is using port fast0/1 in the following example. This example can extend to other application flows that need marked. Marking can by CPU intensive for routers and switches. Always ensure that you have properly sized your equipment for Marking.

  1. Enable QoS on the Switch

    Start in the privileged exec mode:

    switch(config)#mls qos
switch(config)#policy-map mark-signal
switch(config-pmap)#class voice-signal
switch(config-pmap-c)#set dscp cs3
switch(config-pmap-c)#exit
switch(config-pmap)#exit

  2. Create access lists to identify the SIP signaling traffic as it leaves the CIC server

    Start in the privileged exec mode:

    switch(config)#access-list 100 permit tcp any any eq 5060
switch(config)#access-list 100 permit tcp any any eq 8060

  3. Create a Class-Map that uses the Access List

    Start in the privileged exec mode:

    switch (config)#class-map match-all voice-signal
switch(config-cmap)#match access-group 100
switch(config-cmap)#exit

  4. Apply the Class-Map to a Policy

    Start in the privileged exec mode:

    switch(config)#policy-map mark-signal 
switch(config-pmap)#class voice-signal
switch(config-pmap-c)#set dscp cs3
switch(config-pmap-c)#exit
switch(config-pmap)#exit

  5. Apply the Service-Policy to the CIC server interface

    Start in the privileged exec mode:

    switch(config)#int fast 0/12
switch(config-if)#service-policy input mark-signal
switch(config-if)#exit