Installation Guide

IBR Installation Guide
Page 20 of 38 Doc # 770-00023.1
Jan. 23, 2015
IBR automatically records the MAC address of a received packet, the port on which it was received, and
whether the packet has a VLAN designation. When an incoming packet arrives at IBR, the correct port and
VLAN for delivery of the packet is determined by comparing the MAC address of the packet with the
corresponding entry in L2. If the MAC address is not in the L2 table, IBR will send the packet out to all ports
except the one on which it was received, and then record the port and VLAN of the device that responds to the
packet.
When a MAC address in the L2 table has not been used within a preset time (the “aging time”), the MAC
address entry is automatically deleted from the table. The default aging time is three hundred (300) seconds.
Aging time is the only property of the L2 table functionality that can be changed. The L2 table can contain up
to sixty-four thousand entries so that, with a reasonable aging time, there is little chance of an overflow
condition.
Using the CLI “show” command, an operator can display the contents of the L2 table.
5.2 Counters
Counters are implemented as two-dimensional arrays that associate traffic metrics with the corresponding
IBR ports (interfaces). Counters are activated by default and cannot be disabled; however, the contents of
counters can be reset to zero or displayed by operator command. The counters in IBR are listed below
organized the way they would be displayed using the show command.
IBR102 # show interface counters Shows a brief view, not including errors
IBR102 # show interface counters all Shows all except TxQueue
IBR102 # show interface counters detail Shows the following counters
InBytes Bytes received at a port
InUcastPkts Unicast packets received at a port
InMcastPkts Multicast packets received at a port
InBcastPkts Broadcast packets received at a port
OutBytes Bytes sent from a port
OutUcastPkts Unicast packets sent from a port
OutMcastPkts Multicast packets sent from a port
OutBcastPkts Broadcast packets sent from a port
RxPause Pause requests received
TxPause Pause requests sent
IBR102 # show interface counters errors Shows error counters
CrcAlign-Err Frames without an even # of octets or with CRC errors
Collisions Collisions before successful transmission
Symbol-Err Symbol errors
Undersize Frames rcvd that are < 64 bytes
Oversize Frames rcvd that are > 1514 bytes
Fragments Oversized packets sent as fragments
Jabbers Frames longer than 1518 octets
FCS-Err Frames corrupted during transmission
Deferred-Xmit Times xmsn delayed
Single-Col Times only one collision occurred before successful xmsn
Multi-Col Times multiple collisions occurred before successful xmsn
Late-Col Collisions detected after > 512 bits sent
Excess-Col Frames not sent due to excess # of retries
IBR102 # show interface counters txqueue Shows TxQueue counters
Octets TX queue octets