HP A5120 EI Series Configuration Guide

59
Table 11 Comparison process and result on each device
Device
Comparison process
Configuration BPDU on
ports after comparison
Device A
 Port A1 receives the configuration BPDU of Port B1 {1,
0, 1, Port B1}, finds that its existing configuration BPDU
{0, 0, 0, Port A1} is superior to the received
configuration BPDU, and discards the received one.
 Port A2 receives the configuration BPDU of Port C1 {2,
0, 2, Port C1}, finds that its existing configuration
BPDU {0, 0, 0, Port A2} is superior to the received
configuration BPDU, and discards the received one.
 Device A finds that it is both the root bridge and
designated bridge in the configuration BPDUs of all its
ports, and considers itself as the root bridge. It does
not change the configuration BPDU of any port and
starts to periodically send configuration BPDUs.
 Port A1: {0, 0, 0, Port
A1}
 Port A2: {0, 0, 0, Port
A2}
Device B
 Port B1 receives the configuration BPDU of Port A1 {0,
0, 0, Port A1}, finds that the received configuration
BPDU is superior to its existing configuration BPDU {1,
0, 1, Port B1}, and updates its configuration BPDU.
 Port B2 receives the configuration BPDU of Port C2 {2,
0, 2, Port C2}, finds that its existing configuration
BPDU {1, 0, 1, Port B2} is superior to the received
configuration BPDU, and discards the received one.
 Port B1: {0, 0, 0, Port
A1}
 Port B2: {1, 0, 1, Port
B2}
 Device B compares the configuration BPDUs of all its
ports, decides that the configuration BPDU of Port B1 is
the optimum, and selects Port B1 as the root port with
the configuration BPDU unchanged.
 Based on the configuration BPDU and path cost of the
root port, Device B calculates a designated port
configuration BPDU for Port B2 {0, 5, 1, Port B2}, and
compares it with the existing configuration BPDU of
Port B2 {1, 0, 1, Port B2}. Device B finds that the
calculated one is superior, decides that Port B2 is the
designated port, replaces the configuration BPDU on
Port B2 with the calculated one, and periodically sends
the calculated configuration BPDU.
 Root port (Port B1): {0,
0, 0, Port A1}
 Designated port (Port
B2): {0, 5, 1, Port B2}
Device C
 Port C1 receives the configuration BPDU of Port A2 {0,
0, 0, Port A2}, finds that the received configuration
BPDU is superior to its existing configuration BPDU {2,
0, 2, Port C1}, and updates its configuration BPDU.
 Port C2 receives the original configuration BPDU of
Port B2 {1, 0, 1, Port B2}, finds that the received
configuration BPDU is superior to the existing
configuration BPDU {2, 0, 2, Port C2}, and updates its
configuration BPDU.
 Port C1: {0, 0, 0, Port
A2}
 Port C2: {1, 0, 1, Port
B2}

HP A5120 EI Series Specifications

General

Uplink Ports	4 x SFP
Stacking	No
Management	CLI, Web, SNMP
Routing Protocols	RIP, OSPF
Power Supply	AC
MAC Address Table Size	16K
Dimensions	440 x 430 x 44 mm
Operating Temperature	0°C to 45°C
Operating Humidity	10% to 90% non-condensing
Model	HP A5120-24G EI Switch (JG234A)
VLANs	4094