HP 2424M - Manual (Page 12)

HP ProCurve Switch 4000M / 8000M / 2424M / 1600M Reviewer’s Guide
multimedia data performance, particularly if this data is delivered through multicast mechanisms, it is
low variance in latency that is the most important latency measurement for a switch.
2.2.2.1 Backplanes: Chassis vs. Stackable
The HP ProCurve Switch 4000M is positioned as a 10/100Mbps desktop or wiring closet switch. Most
other products in this category, including the HP ProCurve Switch 2424M, are stackable switches. A
quick list of the differences between chassis and stackable solutions is:
Chassis
• Chassis generally have higher backplane speeds than stackable switch backplanes. The stacking
backplane further limits bandwidth between switches as it is almost always lower speed than
the switch backplane. In addition, some vendor stacking solutions use a shared rather than
switched approach for the stacking backplane. The HP ProCurve Switch 2424M uses a fully
switched stacking backplane.
• All ports in the chassis have equal bandwidth access to each other across the backplane
• No stacking hardware or cable is required up to port count capability of each chassis, resulting
in less cabling for the number of ports
• Higher port density possible
Stackable
• Less expensive, particularly at lower port counts
• No loss of ports when interconnecting multiple switches
Overall, the chassis solution is usually a better solution from a throughput and type-of-port flexibility
perspective. A stackable solution is good for users that don’t require the higher backplane bandwidth,
are very price-sensitive, or just prefer it.
2.2.3 Packet Buffer Memory
Both flow control and packet buffer memory are used by the switch to handle momentary packet
congestion. The amount of packet buffer memory used within the HP ProCurve Switch 8000M and
HP ProCurve Switch 1600M varies depending on the port module:
Module Total Memory Per Port Memory
HP ProCurve Switch 10/100Base-TX module 4 MB 512 KB
HP ProCurve Switch 100Base-FX module 2 MB 512 KB
HP ProCurve Switch Gigabit-SX module 4 MB 4 MB
HP ProCurve Switch Gigabit-LX module 4 MB 4 MB
HP ProCurve Switch 2424M Gigabit 8 MB 4 MB
Stacking Module
HP ProCurve Switch 100/1000Base-T module 4 MB 4 MB
HP ProCurve Switch 10Base-FL module 2 MB 512 KB
2.2.4 HP ProCurve Switch 100/1000Base-T Module
The low cost HP ProCurve Switch 100/1000Base-T module implements Gigabit data rates over standard
Category 5 or better UTP copper wiring at up to 100m. The module autosenses 100/1000, full or half
duplex and MDI or MDI-X connections.
The Auto MDI/MDI-X feature is new and makes cabling between two switches or switch to server very
easy as either a straight-through or crossover cable can be used in any of these circumstances.
For customers installing new copper cabling, Category 5e wire is recommended. Existing wiring and all
new installations should be checked to make sure the end-to-end connections (including patch panels
and cross-connect blocks) meet the specs necessary for 1000Base-T. Cable testers suitable for copper
©1998, 1999, 2000 Hewlett-Packard Co Revision 3.2b – 1/15/2000 Page 12 of 36