Cisco Cisco IOS Software Release 12.4(2)XB6
7
Release Notes for the Cisco 3700 Series Integrated Services Routers for Cisco IOS Release 12.4(2)XA
OL-8898-01
New and Changed Information
New Software Features in Cisco IOS Release 12.4(2)XA and 12.4(2)XA1
The following sections describe the new software features supported by the Cisco 3700 series routers for
Release 12.4(2)XA.
Release 12.4(2)XA.
ATM Oversubscription for DSL
The ATM Oversubscription for DSL feature lets you configure bandwidth oversubscription on Cisco
xDSL interfaces up to a defined bandwidth. You can configure variable bit rate (VBR) and unspecified
bit rate plus (UBR+) service classes for permanent virtual circuit (PVC) connections with a sum of
sustainable cell rates (SCRs) greater than the line rate, which means you can configure an infinite
oversubscription amount of bandwidth. Each PVC receives up to its configured SCR value of traffic, and
PVCs with higher SCR values receive more bandwidth.
xDSL interfaces up to a defined bandwidth. You can configure variable bit rate (VBR) and unspecified
bit rate plus (UBR+) service classes for permanent virtual circuit (PVC) connections with a sum of
sustainable cell rates (SCRs) greater than the line rate, which means you can configure an infinite
oversubscription amount of bandwidth. Each PVC receives up to its configured SCR value of traffic, and
PVCs with higher SCR values receive more bandwidth.
To enable ATM oversubscription for DSL, use the ATM oversubscribe factor command in ATM
configuration mode. To disable ATM oversubscription for DSL, use the no form of this command.
configuration mode. To disable ATM oversubscription for DSL, use the no form of this command.
atm oversubscribe factor factor
no atm oversubscribe factor factor
no atm oversubscribe factor factor
To configure unspecified bit rate (UBR) quality of service (QoS) and specify the output peak cell rate
and output minimum guaranteed cell rate for an ATM PVC, PVC range, switched virtual circuit (SVC),
virtual circuit (VC) class, or VC bundle member, use the ubr+ command in the appropriate command
mode. To remove the UBR+ parameters, use the no form of this command.
and output minimum guaranteed cell rate for an ATM PVC, PVC range, switched virtual circuit (SVC),
virtual circuit (VC) class, or VC bundle member, use the ubr+ command in the appropriate command
mode. To remove the UBR+ parameters, use the no form of this command.
ubr+ output-pcr output-mcr [input-pcr] [input-mcr]
no ubr+ output-pcr output-mcr [input-pcr] [input-mcr]
no ubr+ output-pcr output-mcr [input-pcr] [input-mcr]
Multiqueue Command
The multiqueue command enables a priority and a regular (nonpriority) queue for traffic streams. When
the command is enabled and there are multiple classes of packet streams over the same PVC, packets
coming from the streams that have priority values configured in a policy map are sent to the high priority
queue. Packets from all other streams will be sent over the low priority queue. Multiqueue is intended
for configuring DSL lines and permits configuring one data flow in a priority queue. If you have
configured more than one flow in a priority queue, the latency for delay-sensitive traffic flow may not
be guaranteed.
the command is enabled and there are multiple classes of packet streams over the same PVC, packets
coming from the streams that have priority values configured in a policy map are sent to the high priority
queue. Packets from all other streams will be sent over the low priority queue. Multiqueue is intended
for configuring DSL lines and permits configuring one data flow in a priority queue. If you have
configured more than one flow in a priority queue, the latency for delay-sensitive traffic flow may not
be guaranteed.
The multiqueue approach does not work well with applications such as MLPPP with interleave and
Crypto. This is because MLPPP uses the same sequence numbering scheme for interleaved packets as
the multiqueue approach. For example, if there are a voice and two data packets interleaved, the MLPPP
sequence numbers for these packets could be 1 for the first data packet, 2 for the voice packet, and 3 for
a second data packet. In the multiqueue approach, the voice packet with MLPPP sequence number 2
would go out before the data packet with MLPPP sequence number 1. This would result in out-of-order
sequencing of packets as far as MLPPP is concerned, and result in unexpected behavior. The same
problems apply to the Crypto application. The multiqueue approach is disabled by default so that when
MLPPP and the Crypto applications are used with DSL the network will not be disrupted by upgrading
to an image with multiqueue support.
Crypto. This is because MLPPP uses the same sequence numbering scheme for interleaved packets as
the multiqueue approach. For example, if there are a voice and two data packets interleaved, the MLPPP
sequence numbers for these packets could be 1 for the first data packet, 2 for the voice packet, and 3 for
a second data packet. In the multiqueue approach, the voice packet with MLPPP sequence number 2
would go out before the data packet with MLPPP sequence number 1. This would result in out-of-order
sequencing of packets as far as MLPPP is concerned, and result in unexpected behavior. The same
problems apply to the Crypto application. The multiqueue approach is disabled by default so that when
MLPPP and the Crypto applications are used with DSL the network will not be disrupted by upgrading
to an image with multiqueue support.
To enable two queues to prioritize multiple classes of packet streams over the same PVC, use the
multiqueue command in either the PVC- or VC-class configuration modes. To return to a single queue,
use the no form of this command.
multiqueue command in either the PVC- or VC-class configuration modes. To return to a single queue,
use the no form of this command.
multiqueue
no multiqueue
no multiqueue