DM16E1 / DM4E1 Operation and Installation Manual - 204-4001-19 64
8. 10/100BASET ETHERNET REMOTE BRIDGE
The basic function of the Bridge module is to segment a local network, avoiding that all the local Ethernet
traffic is transmitted to the remote equipment, thus wasting bandwidth (capacity).
In order to meet this objective, the Bridge is able to automatically learn the MAC address of the stations
connected to the local network. This way, it can filter traffic coming from the local network and transmit to
the WAN side only those packets corresponding to the MAC address that is not present in the local
network, in addition to broadcast and multicast packets.
The process of filtering packets that will be transmitted does not impose any restriction to the data flow.
The delay introduced by the Bridge processing is of 1 Ethernet frame.
The table of local addresses of the Bridge can store up to 1,000 MAC addresses. In case a station is
inactive for more than 5 minutes, its address will be removed from the table.
It accepts packets up to 1536 bytes, supporting the use of VLANs.
The Bridge has a buffer on the Ethernet Mux transmission direction, which can store up to 322 Ethernet
packets of 1522 bytes. Alternatively, a higher number of smaller packets can be stored.
On the Mux Ethernet transmission direction, there is a buffer for 64 Ethernet packets of 1522 bytes. If
the packets are smaller, more packets can be stored. There is no filtering on this data transmission
direction, because this was already carried out by the Bridge of the remote equipment.
The Bridge card operates at the MAC level of the Ethernet interface. This way, the module is totally
transparent for the upper layer protocols, such as TCP/IP, UDP, DECnet, etc.
os protocolos das camadas superiores, tais como TCP/IP, UDP, DECnet, etc.
The Bridge consists in a card installed inside the equipment. The Ethernet connection is made with an
RJ45 connector available on the rear panel of DM16E1 and DM4E1. The interface is optional, but the
RJ45 connector and the Link led are always mounted on the cabinet.
When Bridge is used, a Bridge card must be present at each side of the connection.
The Bridge card can work on DM16E1/DM4E1 with or without inverse multiplexing.
On the other hand, in cases of operation with inverse multiplexing, data received through the Bridge port
are split into E1 channels according to Figure 25:
MAC from 01-80-C2-00-00-01 to 01-80-C2-00-00-0F are filtered by the bridge card, i
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