Cisco Cisco Extended Care 1.0 Design Guide
4-4
Cisco Extended Care 1.0 Solution Design Guide
OL-30842-01
Chapter 4 Cisco Extended Care Bandwidth Requirements and Quality of Service Recommendations
QoS Best Design Practices for Cisco Extended Care
Table 4-2
Cisco Jabber SDK to Jabber SDK QoS Parameter Recommendations at 512 Kbps
QoS Best Design Practices for Cisco Extended Care
When designing a network to support Cisco Extended Care, QoS best design practices should be
employed wherever possible. These best practices include the following:
employed wherever possible. These best practices include the following:
•
Classification and marking policies should be implemented in Cisco Catalyst hardware as close to
the source of the traffic as possible (e.g., on the access edge switch to which the Cisco Extended
Care System is attached).
the source of the traffic as possible (e.g., on the access edge switch to which the Cisco Extended
Care System is attached).
•
Use Differentiated Services Code Point (DSCP) whenever possible. DSCP provides more
granularity than IP Precedence.
granularity than IP Precedence.
•
Always deploy QoS in hardware, rather than software, whenever a choice exists. QoS policies, like
classification, marking/remarking, and/or policing can all be performed at line rates with zero
Central Processing Unit (CPU) impact in Catalyst switches. Cisco IOS routers, on the other hand,
perform QoS operations in software, resulting in a marginal CPU impact, the degree of which
depends on the platform, the policies, the link speeds, and the traffic flows involved.
classification, marking/remarking, and/or policing can all be performed at line rates with zero
Central Processing Unit (CPU) impact in Catalyst switches. Cisco IOS routers, on the other hand,
perform QoS operations in software, resulting in a marginal CPU impact, the degree of which
depends on the platform, the policies, the link speeds, and the traffic flows involved.
•
Follow industry standards whenever possible, as this extends the effectiveness of your QoS policies
beyond your direct administrative control. For example, if you mark a real-time application, such as
VoIP, to the industry standard recommendation as defined in RFC 3246 (An Expedited Forwarding
Per-Hop Behavior), it receives high priority servicing at every node within your enterprise network.
The relevant standards are listed below in chronological order:
beyond your direct administrative control. For example, if you mark a real-time application, such as
VoIP, to the industry standard recommendation as defined in RFC 3246 (An Expedited Forwarding
Per-Hop Behavior), it receives high priority servicing at every node within your enterprise network.
The relevant standards are listed below in chronological order:
–
Between Cisco’s QoS Baseline and RFC 4594 is the RFC 4594 recommendation to mark Call
Signaling as CS5. Cisco plans to continue marking Call Signaling as CS3 until future business
requirements arise that necessitate another marking migration. Therefore, for the remainder of
this document, RFC 4594 marking values are used throughout, with the one exception of
swapping Call-Signaling marking (to CS3) and Broadcast Video (to CS5). These marking
values are summarized in
Signaling as CS5. Cisco plans to continue marking Call Signaling as CS3 until future business
requirements arise that necessitate another marking migration. Therefore, for the remainder of
this document, RFC 4594 marking values are used throughout, with the one exception of
swapping Call-Signaling marking (to CS3) and Broadcast Video (to CS5). These marking
values are summarized in
Table 4-3
Cisco Marking Recommendations
Parameter
Value
Latency
<150ms
Jitter
0 ms (constant) and 0 ms of jitter
Packet loss
0%
Multiparty Mode (Mcu Call)
Not Supported @ 512
Point To Point w/high BW Endpoint
Good video takes approx. 2 minutes
Point To Point w/controlled BW -
256Kbps (option to set
incoming/outgoing in 2nd Endpoint)
256Kbps (option to set
incoming/outgoing in 2nd Endpoint)
Good video takes approx. 50 seconds