Statistical load distribution, Built-in fault tolerance, Port trunk groups – HP 445946-001 User Manual
Page 37: Before you configure trunks
Ports and trunking
37
Table 7
Ethernet switch port names
Port number
Port alias
13 Downlink13
14 Downlink14
15 Downlink15
16 Downlink16
17 Mgmt
18 Uplink1
19 Uplink2
20 Uplink3
21 Uplink4
Port trunk groups
When using port trunk groups between two switches, you can create an aggregate link operating at up to
forty Gigabits per second, depending on how many physical ports are combined. The switch supports up
to 12 trunk groups per switch, each with up to six ports per trunk group.
The trunking software detects broken trunk links (link down or disabled) and redirects traffic to other trunk
members within that trunk group. You can only use trunking if each link has the same configuration for
speed, flow control, and auto-negotiation.
Statistical load distribution
In a configured trunk group containing more than one port, the load distribution is determined by
information embedded within the data frame. For IP traffic, the switch will calculate the trunk port to
use for forwarding traffic by implementing the load distribution algorithm on value equals to modulus of
(XOR of last 3 bits of Source and last 3 bits of Destination IP address). For non-IP traffic, the switch will
calculate the trunk port to use for forwarding traffic by implementing the load distribution algorithm on
value equals to modulus of (XOR of last 3 bits of Source and last 3 bits of Destination MAC address).
Built-in fault tolerance
Since each trunk group is composed of multiple physical links, the trunk group is inherently fault tolerant.
As long as even one physical link between the switches is available, the trunk remains active.
Statistical load distribution is maintained whenever a link in a trunk group is lost or returned to service.
Before you configure trunks
When you create and enable a trunk, the trunk members (switch ports) take on certain settings necessary
for correct operation of the trunking feature.
Before you configure your trunk, you must consider these settings, along with specific configuration rules,
as follows: