Which option is true when calculating round-trip delay in IP SLA operations?
A.
The processing time on the end routers is only assessed for operations that involve the
responder.
B.
The processing time on the end routers is only assessed for operations that involve the
transmitter.
C.
The processing time on the end routers is only assessed for operations that involve both the
respond.
D.
The processing time on the end routers is not assessed for neither the responder nor the
transmitter.
Explanation:
The Cisco IOS IP SLAs Responder is a component embedded in the destination Cisco routing
device that allows the system to anticipate and respond to Cisco IOS IP SLAs request packets.
The Cisco IOS IP SLAs Responder provides an enormous advantage with accurate
measurements without the need for dedicated probes and additional statistics not available via
standard ICMP-based measurements. The patented Cisco IOS IP SLAs Control Protocol is used
by the Cisco IOS IP SLAs Responder providing a mechanism through which the responder can be
notified on which port it should listen and respond. Only a Cisco IOS device can be a source for a
destination IP SLAs Responder.
Figure 2 shows where the Cisco IOS IP SLAs Responder fits in relation to the IP network. The
Cisco IOS IP SLAs Responder listens on a specific port for control protocol messages sent by a
Cisco IOS IP SLAs operation. Upon receipt of the control message, the responder will enable the
specified UDP or TCP port for the specified duration. During this time, the responder accepts the
requests and responds to them. The responder disables the port after it responds to the Cisco IOS
IP SLAs packet, or when the specified time expires. For added security, MD5 authentication for
control messages is available.
Enabling the Cisco IOS IP SLAs Responder on the destination device is not required for all Cisco
IOS IP SLAs operations. For example, if services that are already provided by the destination
router (such as Telnet or HTTP) are chosen, the Cisco IOS IP SLAs Responder need not be
enabled. For non-Cisco devices, the Cisco IOS IP SLAs Responder cannot be configured and
Cisco IOS IP SLAs can send operational packets only to services native to those devices.