PowerConnect B-Series FCX Configuration Guide
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53-1002266-01
Overview
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4. If the IP forwarding cache does not have an entry for the packet, the Layer 3 Switch checks the
IP route table for a route to the packet destination. If the IP route table has a route, the Layer 3
Switch makes an entry in the session table or the forwarding cache, and sends the route to a
queue on the outgoing ports:
•
If the running-config contains an IP access policy for the packet, the software makes an
entry in the session table. The Layer 3 Switch uses the new session table entry to forward
subsequent packets from the same source to the same destination.
•
If the running-config does not contain an IP access policy for the packet, the software
creates a new entry in the forwarding cache. The Layer 3 Switch uses the new cache entry
to forward subsequent packets to the same destination.
The following sections describe the IP tables and caches:
•
ARP cache and static ARP table
•
IP route table
•
IP forwarding cache
•
Layer 4 session table
The software enables you to display these tables. You also can change the capacity of the tables on
an individual basis if needed by changing the memory allocation for the table.
ARP cache and static ARP table
The ARP cache contains entries that map IP addresses to MAC addresses. Generally, the entries
are for devices that are directly attached to the Layer 3 Switch.
An exception is an ARP entry for an interface-based static IP route that goes to a destination that is
one or more router hops away. For this type of entry, the MAC address is either the destination
device MAC address or the MAC address of the router interface that answered an ARP request on
behalf of the device, using proxy ARP.
ARP cache
The ARP cache can contain dynamic (learned) entries and static (user-configured) entries. The
software places a dynamic entry in the ARP cache when the Layer 3 Switch learns a device MAC
address from an ARP request or ARP reply from the device.
The software can learn an entry when the Layer 2 Switch or Layer 3 Switch receives an ARP request
from another IP forwarding device or an ARP reply. Here is an example of a dynamic entry:
Each entry contains the destination device IP address and MAC address.
Static ARP table
In addition to the ARP cache, Layer 3 Switches have a static ARP table. Entries in the static ARP
table are user-configured. You can add entries to the static ARP table regardless of whether or not
the device the entry is for is connected to the Layer 3 Switch.
NOTE
Layer 3 Switches have a static ARP table. Layer 2 Switches do not.
IP Address MAC Address Type Age Port
1 207.95.6.102 0800.5afc.ea21 Dynamic 0 6
Содержание PowerConnect B-FCXs
Страница 1: ...53 1002266 01 18 March 2011 PowerConnect B Series FCX Configuration Guide ...
Страница 136: ...94 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Viewing information about software licenses 4 ...
Страница 228: ...186 PowerConnect B Series FCX Configuration Guide 53 1002266 01 PowerConnect B Series FCX hitless stacking 5 ...
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Страница 230: ...188 PowerConnect B Series FCX Configuration Guide 53 1002266 01 PowerConnect B Series FCX hitless stacking 5 ...
Страница 248: ...206 PowerConnect B Series FCX Configuration Guide 53 1002266 01 IPv6 management commands 7 ...
Страница 346: ...304 PowerConnect B Series FCX Configuration Guide 53 1002266 01 802 1s Multiple Spanning Tree Protocol 8 ...
Страница 374: ...332 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Jumbo frame support 9 ...
Страница 424: ...382 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Virtual Switch Redundancy Protocol VSRP 10 ...
Страница 568: ...526 PowerConnect B Series FCX Configuration Guide 53 1002266 01 CLI examples 14 ...
Страница 588: ...546 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Sample application 15 ...
Страница 674: ...632 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Enabling or disabling layer 2 switching 19 ...
Страница 684: ...642 PowerConnect B Series FCX Configuration Guide 53 1002266 01 VLAN based mirroring 20 ...
Страница 724: ...682 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Reading CDP packets 23 ...
Страница 768: ...726 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Clearing cached LLDP neighbor information 24 ...
Страница 930: ...888 PowerConnect B Series FCX Configuration Guide 53 1002266 01 26 ...
Страница 948: ...906 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Configuring MLD snooping 27 ...
Страница 962: ...920 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Displaying CPU utilization statistics 28 ...
Страница 1022: ...980 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Displaying OSPF information 29 ...
Страница 1142: ...1100 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Clearing diagnostic buffers 30 ...
Страница 1258: ...1216 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Using Secure copy with SSH2 33 ...
Страница 1314: ...1272 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Displaying port security information 35 ...
Страница 1348: ...1306 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Example configurations 36 ...
Страница 1406: ...1364 PowerConnect B Series FCX Configuration Guide 53 1002266 01 IP source guard 39 ...
Страница 1422: ...1380 PowerConnect B Series FCX Configuration Guide 53 1002266 01 SNMP v3 Configuration examples 40 ...