Port Features
Page 38 7705 SAR OS Interface Configuration Guide
If autonegotiation is on for an Ethernet port, enabling and disabling of IEEE 802.3x Flow
Control is autonegotiated for receive and transmit directions separately. If autonegotiation is
turned off, the reception and transmission of IEEE 802.3x Flow Control is enabled by
default and cannot be disabled.
Ethernet OAM
802.3ah Clause 57 (EFM OAM) defines the Operations, Administration, and Maintenance
(OAM) sublayer, which is a link level Ethernet OAM that is supported on 7705 SAR
Ethernet ports configured as network ports. It provides mechanisms for monitoring link
operations such as remote fault indication and remote loopback control. Ethernet OAM
gives network operators the ability to monitor the health status of Ethernet links and quickly
determine the location of failing links or fault conditions.
Because some of the sites where the 7705 SAR will be deployed will only have Ethernet
uplinks, this OAM functionality is mandatory. For example, mobile operators must be able
to request remote loopbacks from the peer router at the Ethernet layer in order to debug any
connectivity issues. EFM OAM provides this capability.
EFM OAM is supported on network Ethernet ports only. The access ports can be configured
to tunnel the OAM traffic originated by the far-end devices.
EFM OAM has the following characteristics.
• All EFM OAM, including loopbacks, operate on point-to-point links only.
• EFM loopbacks are always line loopbacks (line Rx to line Tx).
• When a port is in loopback, all frames (except EFM frames) are discarded. If
dynamic signaling and routing is used (dynamic LSPs, OSPF routing), all services
also go down. If all signaling and routing protocols are static (static routes, LSPs,
and service labels), the frames are discarded but services stay up.
The following EFM OAM functions are supported:
• OAM capability discovery
• configurable transmit interval with an Information OAM PDU
• active or passive mode
• OAM loopback
• OAM PDU tunneling (for Epipe service)
For information on Epipe service, refer to the 7705 SAR OS Services Guide.
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