Cisco C8510-SRP - Switch Route Processor Instrukcja Użytkownika Pobierz pdf (Strona 10)

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Rich QoS Switching Fabric and Policy-Enabled Networking

The Catalyst 8500 series incorporates a centralized shared-memory switching fabric that is nonblocking and low latency. The rich QoS

capabilities of the switching fabric provide customers very granular trafﬁc management capabilities. Rich QoS mechanisms such as WRR

queue scheduling and PFQ allow prioritization of mission-critical and delay-sensitive trafﬁc. Per-queue drop thresholds provide differentiated

loss priorities for prioritizing applications during periods of congestion. Customers also have the ability to provision, control, and manage

bandwidth in the network by enabling features such as trafﬁc policing and trafﬁc shaping that are unique to the Catalyst 8500 architecture.

The fast packet memory associated with the switching fabric is allocated in a dynamic fashion on a per-queue (ﬂow) basis. Dynamic memory

allocation policies, conﬁgurable queue scheduling weights, and user-deﬁned queue thresholds all provide ﬂexible support for managing trafﬁc

and minimizing the probability of packet loss.

The rich QoS capabilities of the Catalyst 8500 series are very useful in allocating bandwidth to server farms and fulﬁlling bandwidth and

delay reservation requests generated by servers using RSVP. However, this complexity needs to be easily manageable for large-scale networks.

CiscoAssure Policy Networking provides customers with a simple way to deﬁne policies using a graphical user interface that speciﬁes the

relative prioritization of users and applications on the network. Using CiscoAssure policy servers and the Catalyst 8500, customers can protect

mission-critical trafﬁc and enable delay-sensitive applications.

Figure 7 Rich QoS Switching Fabric with PFQ and WRR, Rate and Strict Priority Queue Scheduling

• Ensures control traffic promptly gets to CPU

• Custom Priority Policy

Strict Priority Scheduler

Per-Flow Queuing

WRR Queue Scheduler

Output Port

Low

Precedence

High

Precedence

RSVP Bursty

RSVP

Peak = Ave

CBR, VBR,

SCR, MCR

Rate Queue Scheduler

NOW

• Ensures exact bandwidth and delay limits

for CBR, SCR in VBR, MCR in ABR or

ATM CIR

• Ensures exact bandwidth and delay for

VoATM or VoIP traffic

Urgent OSPF,

BGP, UNI/PNNI

Strict Priority

Figure 8 CiscoAssure Policy Networking and Catalyst 8500 Provide Simple

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Cisco C8510-SRP - Switch Route Processor Instrukcja Użytkownika Strona 10