Installation Guide

IBR Installation Guide

Page 18 of 32 Doc # 770-00001-3

Aug. 30, 2013

IBR58 (config) #

4.18 Establishing A Radio Link

IBRs will automatically establish a link using the best frequencies to optimize data

throughput. IBR has a software feature called “Pointing Tool” that will aid in quickly and

properly aligning IBRs for best link performance. It will not be necessary to use this feature

in a laboratory setting where the two ends of a link are within sight of one another.

Use of the pointing tool is discussed in detail in the section titled Installing IBR.

5. MAC Address Table & Counters

IBR contains one table and twenty counters.

5.1 MAC Address Table

The MAC Address table, sometimes referred to as the L2 (or Layer 2) table, associates MAC

addresses with their respective VLAN’s and ports. L2 is the only table in IBR and cannot be

deactivated.

When a packet is received by IBR, IBR automatically records the MAC address of the received

packet and the port on which it was received. 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 L2, 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”), that entry is automatically deleted from the table. The default aging time is three

hundred (300) seconds; however, aging time is a user-configurable property. Aging time is

the only property of L2 that can be changed. L2 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 L2.

5.2 Counters

Counters are implemented as two-dimensional arrays that associate traffic data 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. Counters are identified by the names shown below.

(a) InBytes Bytes received at a port

(b) InUcastPkts ------------ Unicast packets received at a port

(d) InBcastPkts ------------ Broadcast packets received at a port

(e) OutBytes Bytes sent from a port

(f) OutUcastPkts ---------- Unicast packets sent from a port

(g) OutMcastPkts Multicast packets sent from a port

(h) OutBcastPkts ---------- Broadcast packets sent from a port

(i) CrcAlign-Err Frames rcvd that don’t have an even # of octets or have CRC errors

(j) Dropped-Bad-Pkts --- Rcvd packets dropped for errors

(k) Collisions Collisions before successful transmission

(l) Symbol-Err ------------ Symbol errors

(m) Undersize Frames rcvd that are < 64 bytes

(n) Oversize ---------------- Frames rcvd that are > 1514 bytes

(o) Fragments Oversized packets sent as fragments