Edge-Core ECS4510-28P User Manual page 654

| General IP Routing
C 18
HAPTER
IP Routing and Switching
IP R S
OUTING AND WITCHING
Figure 396: Virtual Interfaces and Layer 3 Routing
Inter-subnet traffic (Layer 3 switching)
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Intra-subnet traffic (Layer 2 switching)
IP Switching (or packet forwarding) encompasses tasks required to forward
packets for both Layer 2 and Layer 3, as well as traditional routing. These
functions include:
Layer 2 forwarding (switching) based on the Layer 2 destination MAC
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address
Layer 3 forwarding (routing):
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Based on the Layer 3 destination address
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Replacing destination/source MAC addresses for each hop
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Incrementing the hop count
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Decrementing the time-to-live
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Verifying and recalculating the Layer 3 checksum
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If the destination node is on the same subnetwork as the source network,
then the packet can be transmitted directly without the help of a router.
However, if the MAC address is not yet known to the switch, an Address
Resolution Protocol (ARP) packet with the destination IP address is
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Routing
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