Medium Access Control (MAC) and Physical Layer (PHY) - CISE

4-June-07 P1901_PRO_016_r0
A node performing the registration in the neighbor BPL cell will have a MID different and it will be different from
0x1FFFFF and 0x130001. Under these conditions the node must be accepted avoiding any authentication process,
also the master node knows that is not a node from its network and must avoid transmit any data through the BPL
port.
Failing registration
The maximum time specified for the registration of the border node is 120 seconds
When the timer expires, the HE has to select a new border node to complete negotiation. The HE is the node that
monitories the registration timer, in this way no new packets are needed, even if the border node designated is
switched off the HE restarts the protocol by itself.
The formerly designated border node has to activate the registration timer like the master and when the timer
expires it assumes that it is not border node anymore until a new BNDP is received.
Intermittent transmission
To perform successfully the negotiation among BPL cells it is necessary to get free interference periods, because the
transmissions within the own BPL cell will ruin the registration.
A HE can decide by itself to stop the transmissions within its network avoiding new token generation, but any other
node cannot because its master will regenerate the token.
When the HE receives a BNDA it starts a period so called “INTERMITTENT TRANSMISSION” [IT].
During the status of Border Node a modem can generate as many BNDAs as needed to complete the negotiation.
The default silence time 2 sec, followed by a normal transmission period of 1 sec. It will have 5 silence periods. So
the overall IT will last 15 seconds.
SPANNING TREE
In a network, a spanning tree is a path or collection of paths that represent connections between nodes. To be called
a spanning tree, the tree must cover every possible path in a network. A minimal spanning tree is one that covers all
possible paths, does so with as few segments as possible, and makes sure there are no loops (closed paths) in the
network.
The IEEE 802.1 recommendations provide an algorithm for finding a spanning tree in any network.
Submission page 276 UPA-OPERA