Information Technology Reference
In-Depth Information
bootup.
An AppleTalk networking client displays “Access to your AppleTalk network has been
interrupted. To re-establish your connection, open and close the AppleTalk control panel.”
It is also possible that the AppleTalk client's Chooser application either will not display a
zone list or will display an incomplete zone list.
The initial connectivity delay is also frequently seen in a switched environment in which a network
administrator updates software or drivers. In this case, a vendor may optimize the drivers so that network
initialization procedures happen earlier in the client's startup process (before the switch is ready to
process the packets).
With the various features that are now included in some switches, it can take close to a minute for a
switch to begin servicing a newly connected workstation. This delay would affect the workstation every
time that it is turned on or rebooted. The four main features that cause this delay are listed here:
•
Spanning-Tree Protocol
•
EtherChannel negotiation
•
Trunking negotiation
•
Link speed/duplex negotiation between the switch and the workstation
These four features are listed in order of causing the most delay (Spanning-Tree Protocol) to causing the
least delay (speed/duplex negotiation). A workstation connected to a switch usually does not cause
spanning-tree loops, usually does not need EtherChannel, and usually does not need to negotiate a
trunking method. (Disabling link speed/detection negotiation can also reduce port delay, if you need to
optimize your startup time as much as possible.)
This section shows how to implement startup speed-optimization commands on three Catalyst switch
platforms. In the timing sections, we show how the switch port delay is reduced and by how much.
Contents
The following topics will be covered in this section:
•
Background
•
How to reduce startup delay on the Catalyst 4000/5000/6000 switch
•
Timing tests on the Catalyst 5000
•
How to reduce startup delay on the Catalyst 2900XL/3500XL switch
•
Timing tests on the Catalyst 2900XL
•
How to reduce startup delay on the Catalyst 1900/2800 switch
•
Timing tests on the Catalyst 1900
•
An additional benefit to PortFast
The terms
workstation
,
end station
, and
server
are all used interchangeably in this section to refer to any
device directly connected to a switch by a single NIC card. These terms may also refer to devices with
multiple NIC cards in which the NIC card is used only for redundancy—in other words, the workstation
or server is not configured to act as a bridge; it just has multiple NIC cards for redundancy.
