Cisco MWR 1941-DC - 1941 Mobile Wireless Router Software Configuration Manual page 25

Chapter 1 Overview of the Cisco MWR 1941-DC Router
HSRP
Cisco's Hot Standby Router Protocol (HSRP) is used to control which router is active and which is
standby. HSRP uses a priority scheme to determine which HSRP-configured router is to be the default
active router. Priority is determined first by the configured priority value, and then by the IP address. In
each case a higher value is of greater priority.
IP-RAN Implementation Updates
This section lists MWR 1941-DC router product updates:
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OL-11503-01
Traffic Recovery Over MLP After T1 Failure
With Cisco IOS Release 12.2(8)MC2b and later, you can use the keepalive interface configuration
command to configure traffic over an MLP link to recover within 6 second if a T1 failure should
occur.
ACFC and PFC Support on PPP Multilink Interfaces
With Cisco IOS Release 12.2(8)MC2c and later, by default, Address and Control Field Compression
(ACFC) and Protocol Field Compression (PFC) are enabled on PPP interfaces. Both features are
always enabled and will be negotiated on all serial interfaces.
If upgrading for this support, ensure that you upgrade the MGX-RPM-1FE-CP back card
Note
images first. After doing so, immediately upgrade all MWR 1941-DC routers connected to
the MGX-RPM-1FE-CP back card.
Ignore IP ID Field Delta in cUDP Packet Flows
With Cisco IOS Release 12.2(8)MC2c and later, by default, the ability to ignore IP ID field delta in
cUDP traffic flows is enabled. This ability eliminates the need to send information about the IP
header ID field in compressed packets. The decompressor saves the original ID field from the full
header packet and generates an ID field by incrementing it by one for each decompressed packet.
This feature improves processing efficiency; helping to minimize dropped packets and link
saturation.
Link Noise Monitor
Noise on T1 and E1 links that span between the BTS and central office can affect voice quality for
mobile users to the point where it becomes unacceptable. Therefore, with Cisco IOS release
12.2(8)MC2d and later, you can configure the Link Noise Monitor (LNM) on the MWR 1941-DC
router to monitor the quality of individual links in a multilink bundle. The LNM provides the ability
to detect, alert, and remove noisy links from a bundle based on user-defined thresholds and
durations. For more information on the LNM feature, see
section on page 4-21.
First Two Packets Sent with Full cUDP Headers
With Cisco IOS Release 12.2(8)MC2d and later, at the start of a call flow, the MWR 1941-DC router
and the MGX 8850 RPM-PR back card send the first two packets of the flow with full headers. This
feature helps to minimize the loss of cUDP headers (and therefore misrouted packets) in noisy
and/or congested networks.
Cisco MWR 1941-DC Mobile Wireless Edge Router Software Configuration Guide
Cisco IOS Software Features
"Configuring the Link Noise Monitor"
1-7