Zte ZXDSL 9210 (V3.1), Техническое руководство

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ZXDSL 9210 (V3.1) Broadband Universal Access Equipment Technical Manual
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establishes a high-performance link between a pair of systems. Besides, when a
certain link becomes invalid, though available bandwidth is reduced, the
aggregation link is still able to run normally.
Simply speaking, the link aggregation technology means binding multiple
point-to-point connections between two pieces of Ethernet equipment to form a
logic connection. This logic connection belongs to the data link layer in the
hierarchical model in the OSI. For upper-layer network, a link aggregation logic
port is completely the same as a common MAC layer port because they have the
same attributes and provide the same functions.
The TRUNKING module runs on the SCBF and performs TRUNKING settings
for uplink interfaces, but VDSL user ports and ADSL user ports do not support
TRUNKING.
3. IGMP SNOOPING module
The IGMP SNOOPING protocol enables users to enable the IGMP snooping
function. IGMP defines a process which enables an IP terminal system to notify
the router/switch in its LAN and add/exit from a certain IP multicast group.
A switch sends an IGMP query regularly to access whether there is any
workstation expecting to add (or stay) a multicast group.
The active equipment which expects to join in a group or update the ID of its
members makes a response in the form of an IGMP member. The member report
takes the multicast address of the group to be added or updated as its destination
address.
The switch detects these reports and determines based on them whether there is
at least a workstation in LAN expecting to receive network traffic sent to this
multicast address.
Users can enable the IGMP snooping function to enable a switch to detect these
messages. Then, the switch creates entries in a filtering table and guides those
frames which take a group as its destination address to those ports leading to
group members. If a certain port reaches at least a multicast group member, this
port joins in the output list of filtering table entries corresponding to multicast
addresses.