Specifications

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Cisco MWR 2941 Mobile Wireless Edge Router Software Configuration Guide, Release 12.2(33)MRB
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Chapter 1 Cisco MWR 2941 Router Overview
Features
Clocking is typically distributed from the core network outward to the BTS or Node B at the network
edge. The Cisco MWR 2941 receives and transmits clocking information using any of the following
ports:
• T1/E1
• Ethernet (GigabitEthernet and FastEthernet)
• DSL
• BITS/SYNC port
• 1PPS
• 1.544Mhz
• 2.048Mhz
• 10Mhz
Precision Timing Protocol (PTP)
The Cisco MWR 2941 supports the Precision Time Protocol (PTP) as defined by the IEEE 1588-2008
standard. PTP provides for accurate time synchronization on over packet-switched networks. Nodes
within a PTP network can act in one of the following roles:
• Grandmaster—A device on the network physically attached to the primary time source. All other
clocks are ultimately synchronized to the grandmaster clock.
• Ordinary clock—An ordinary clock is a 1588 clock with a single PTP port that can serve in one of
the following roles:
– Master mode—Distributes timing information over the network to one or more slave clocks,
thus allowing the slave to synchronize its clock to the master.
– Slave mode—Synchronizes its clock to a master clock.
• Boundary clock—The device participates in selecting the best master clock and can act as the master
clock if no better clocks are detected.
• Transparent clock—A device such as a switch that calculates the time it requires to forward traffic
and updates the PTP time correction field to account for the delay, making the device transparent in
terms of timing calculations.
Note The Cisco MWR 2941 does not currently act as a boundary clock or a transparent clock.
Note The 1588-2008 standard defines other clocking devices that are not described here.
PTP Domains
PTP devices use a best master clock algorithm to determine the most accurate clock on a network and
construct a clocking hierarchy based on the grandmaster clock. A given clocking hierarchy is called a
PTP domain.