The 7705 SAR supports the TWAMP server and the session reflector functions, as shown in Figure: 7705 SAR as TWAMP Server and Session Reflector.
The 7705 SAR plays a passive role: the TWAMP control client initiates the control session with the 7705 SAR in order to negotiate the following:
the tests to be executed
the security protocol to be used
the port to be used
The 7705 SAR responds, and when the negotiation is complete, the 7705 SAR performs the following:
timestamps the TWAMP packets upon reception
processes the TWAMP packets and generates a response
timestamps the packets again before transmitting the response packets
TWAMP is supported on all IPv4 interfaces and on the base router of any interface address, including the system and loopback IP addresses. Any IP address can be used to terminate TWAMP control and test packets.
Datapath timestamping in both ingress and egress directions for TWAMP frames is supported on all datapath Ethernet ports on the following adapter cards, modules, and standalone nodes:
adapter cards
2-port 10GigE (Ethernet) Adapter card
6-port Ethernet 10Gbps Adapter card (high accuracy when using IEEE 1588v2 PTP time source)
8-port Gigabit Ethernet Adapter card (high accuracy when using IEEE 1588v2 PTP time source)
10-port 1GigE/1-port 10GigE X-Adapter card (high accuracy when using IEEE 1588v2 PTP time source)
Packet Microwave Adapter card (high accuracy when using IEEE 1588v2 PTP time source)
modules
2-port 10GigE (Ethernet) module
4-port SAR-H Fast Ethernet module
6-port SAR-M Ethernet module
standalone nodes
7705 SAR-A (high accuracy when using IEEE 1588v2 PTP time source)
7705 SAR-Ax (high accuracy when using IEEE 1588v2 PTP time source)
7705 SAR-H (high accuracy when using IEEE 1588v2 PTP time source)
7705 SAR-Hc (high accuracy when using IEEE 1588v2 PTP time source)
7705 SAR-M (high accuracy when using IEEE 1588v2 PTP time source)
7705 SAR-Wx (high accuracy when using IEEE 1588v2 PTP time source)
7705 SAR-X (high accuracy when using IEEE 1588v2 PTP time source)
A 7705 SAR node using GNSS or IEEE 1588v2 PTP for time of day/phase recovery can perform high-accuracy timestamping for TWAMP packets. See the 7705 SAR Basic System Configuration Guide for information about node timing sources.
CSM-based egress timestamping for TWAMP is supported on:
all TDM cards
2-port OC3/STM1 Channelized Adapter card
4-port DS3/E3 Adapter card
4-port OC3/STM1 Clear Channel Adapter card
16-port T1/E1 ASAP Adapter card
32-port T1/E1 ASAP Adapter card
Ethernet ports bound to a routed VPLS interface, where the frames are processed via the VPLS instance before reaching the IP interface
For information about how to configure the TWAMP server and the TWAMP command hierarchy, see the OAM commands for TWAMP.
The 7705 SAR supports a show>test-oam>twamp>server command that displays information about the TWAMP server configuration and statistics, and the clients associated with each server address prefix. See the Show Commands for more information. The 7705 SAR also supports a dump command that displays statistics for dropped connections, dropped connection states, rejected sessions, and dropped test packets. See Dump Test-OAM Commands for more information.