Which two mechanisms can provide fast Layer 2 down detection in Frame Relay networks? (Choose two.)
Click on the arrows to vote for the correct answer
A. B. C. D. E.AC.
Frame Relay is a widely used WAN technology that uses virtual circuits to transport data over a shared network. In Frame Relay, Layer 2 down detection is an important feature that helps identify and recover from link failures quickly.
There are several mechanisms available in Frame Relay networks that can provide fast Layer 2 down detection. The two most common mechanisms are:
Asynchronous LMI: Asynchronous LMI (ALMI) is a Frame Relay protocol that provides fast Layer 2 down detection. It works by sending a keepalive message to the remote end of the virtual circuit at regular intervals. If the remote end fails to respond to the keepalive message within a certain period, the local end assumes that the link is down and takes appropriate action.
A-bit signaling: A-bit signaling is another mechanism that can provide fast Layer 2 down detection in Frame Relay networks. It works by setting a special bit (A-bit) in the Frame Relay header to indicate that the frame is a signaling frame. A-bit signaling is used to convey information about the state of the virtual circuit, including whether the link is up or down.
Other mechanisms that can provide fast Layer 2 down detection in Frame Relay networks include:
Millisecond LMI timers: This mechanism involves configuring the LMI (Link Management Interface) timers to send keepalive messages at shorter intervals. This can help detect link failures faster.
Frame BFD Lite: Frame BFD Lite (Bidirectional Forwarding Detection) is a protocol that provides fast failure detection for Layer 2 and Layer 3 networks. It works by exchanging control packets between the two ends of a virtual circuit to monitor the link status.
Section 9 LMI convergence: This mechanism involves configuring the LMI to use Section 9 signaling, which provides faster convergence times than other signaling methods.
In conclusion, the two mechanisms that can provide fast Layer 2 down detection in Frame Relay networks are Asynchronous LMI and A-bit signaling. However, other mechanisms such as millisecond LMI timers, Frame BFD Lite, and Section 9 LMI convergence can also be used to provide fast failure detection.