Cisco 10000 - Manual (Page 66)

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Cisco 10000 Series Router Software Configuration Guide
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Chapter 2 Scalability and Performance
Scaling Enhancements in Cisco IOS Release 12.3(7)XI1
Scaling Enhancements in Cisco IOS Release 12.3(7)XI1
Cisco IOS Release 12.3(7)XI1 provides increased limits with FIB scaling, policy-map scaling, and
queue scaling.
FIB Scaling
The FIB is a routing table that is used to look up the next hop route for the destination IP address and
the reverse path forwarding (RPF) route using the source IP address. The FIB Scaling feature implements
the following changes:
• Up to 1 million routes in the global FIB table are supported without MPLS VPN configuration.
• Total number of virtual routing and forwarding instances (VRFs) supported is 4095.
– Up to 100 routes per VRF with 4095 VRFs configured.
– Up to 70 routes per VRF with 4095 VRFs configured, plus 200,000 global BGP routes.
– Up to 600 routes per VRF with 1000 or fewer VRFs configured.
Policy-Map Scaling
The Policy-Map Scaling feature increases the system-wide number of quality of service (QoS) policy
maps that you can configure. Depending on the complexity of your configuration, the
Cisco 10000 series router supports up to 4096 policy maps. In complex configurations the maximum
number of policy maps can be as small as a few hundred. Additionally, when you use percent-based
policing in a service policy, the system may convert a single customer-configured service to multiple
service policies (which count against the 4096 limit). The system uses one such service policy for each
different speed interface that uses a service policy with percent-based policing
Each policy-map command counts as one policy map and applying the same policy map on different
speed interfaces also counts as an extra policy map. The policy-map command syntax is unchanged. The
maximum number of classes that you can configure in a policy is 127.
Queue Scaling
The Queue Scaling feature increases the total number of queues that VTMS supports to 131,072. Of the
total number, 254 queues are available for high speed interfaces, and 130,816 queues are available for
low speed interfaces. This increase allows the support of the 31,500 priority queues (of 131,072 total
queues) on 31,500 sessions or interfaces.
Each interface includes a class-default queue and a system queue. If you attach an output policy map
with 1 priority queue and 1 class-based weighted fair queue (PQ/CBWFQ) to each of the 31,500
interfaces, the number of priority queues is 31,500 and the total number of queues is 31,500 x 4, or
126,000 queues.
The maximum number of queues per link remains at 32, of which 29 are user-configurable because there
is 1 class-default queue, 1 system queue, and 1 reserved queue.
To support 131,072 queues, the queue limits range has changed. For high-speed interfaces (an interface
that has a speed greater than 622 Mbps), the queue limit range is 128 to 65,536. For low-speed interfaces
the queue limit range is 8 to 4,096. Because the total number of packet buffers for queue limits is
4,194,304, the average queue depth is less than or equal to 32 per queue with 131,072 queues configured.