MLFR bundle link integrity protocol

FRF.16.1 defines a MLFR Bundle Link Integrity Protocol which verifies the serviceability of a member link. If a problem is found on the member link the link integrity protocol identifies the problem, flags the link as unusable, and adjusts the Bundle’s available bandwidth. For MLFR Bundles the link integrity protocol is always enabled.

For each member link of a bundle the link integrity protocol does the following:

Specifically, the MLFR Bundle Link Integrity Protocol defines the following control messages:

The control messages are encapsulated in a single-fragment frame where the C-bit, the B-bit, and the E-bit are all set. The details of the message format are given in FRF.16.1. Table 1 lists the user configured control parameters with values as specified in FRF.16.1.

Table 1. FRF.16.1 values
Parameter Default value Minimum value Maximum value

Timer T_HELLO

10 seconds

1 second

180 seconds

Timer T_ACK

4 seconds

1 second

10

Count N_MAX_RETRY

2

1

5

T_HELLO Timer - this timer controls the rate at which hello messages are sent. Following a period of T_HELLO duration, a HELLO message is transmitted onto the Bundle Link.

Note that T_HELLO Timer is also used, during the Bundle Link adding process, as an additional delay before re-sending an ADD_LINK message to the peer Bundle Link when this peer Bundle Link does not answer as expected.

T_ACK Timer - this timer defines the maximum period to wait for a response to any message sent onto the Bundle Link before attempting to retransmit a message onto the Bundle Link.

N_RETRY - this counter specifies the number of times a retransmission onto a Bundle Link is attempted before an error is declared and the appropriate action taken.