IP178G datasheet(29/76 Pages) ETC2

29 / 76 page

IP178G

Data Sheet

29 / 76

December 19, 2012

IP178G-DS-R01.3

A copy of port5 output traffic

Port5

Port4

Port0

A copy of port4 output traffic

Figure 9 Port Mirroring Security Block Diagram

4.9

Link Aggergation

Link aggregation is used to provide a large throughput between two network nodes by using the

method of grouping a set of ports. If some of ports are in a trunk group, all ports in that trunk group shall

be in the same VLAN group.

Each trunk group may comprise 2 to 6 ports. Designer can configure the trunk group members

individually by writing non-zero values to the corresponding bits of a port in the registers 22.12[7:0] and

22.13[7:0] for trunk group 0 and trunk group 1. A trunk channel works as if a “big” port with multiple times

of bandwidth. If the destination port of a packet is un-link, IP178G forwards the packet to the other port of

the trunk (auto recovery).

Trunk 0:

Port1 un-link

port2

port1

port0

Traffic is changed from port 1

to port0

Figure 10 Trunk Channel Behavior Block Diagram

To fully utilize the bandwidth in a trunk channel, IP178G supports load balance function. A physical

port of a trunk forwards a packet only if the trunk group of the packet matches the group setting of the

port. That is, when a packet is forwarded to a port in a trunk, its destination port is according to trunk

group.

The aggregation mode determines which index would be used to search aggregation mask table.

Here provide four ways: the four LSB of the SMAC, the four LSB of the DMAC, the four LSB of the SMAC

xor DMAC, and Source port ID.

Link aggregation function only uses a 3-bit index to search aggregation mask table. To achieve it,

the aggregation index selection is used to extract a 3-bit index from the mentioned in AGGR_MODE.

If the destination port of a trunk is un-link, the packet will be forward the port shifted by 2. If the port

is un-link, too, the packet will be forward the port shifted by 3. For example, if port 3 is un-link, its packet

will be forwarded to port 5. If port 5 is un-link, too, the packet will be forwarded to port 4.

IP178G Datasheet(PDF) 29 Page - List of Unclassifed Manufacturers