Uplinks? should I use Line card or Supervisor?

[todd.martin-02]

Share your philosophy on uplinks. What are the pro's and cons of using the Supervisor engine?

The 6513's are the Access to the Server Farm.

I can spare 2 ports on a line card so ports are not in short supply.

[Kevin Dorrell]

I would put them on the supervisor card. If you lose the supervisor, you are going to lose the whole switch anyway, so there's not much point in occupying line card ports. If you lose the line card, then you can replace it on the fly, but that is not much use to you if you also lose the uplinks.

If you have redundant supervisors, I prefer to put one uplink on each supervisor. That way you can lose either supervisor without losing anything. Use uplinkfast or similar.

Kevin Dorrell

Luxembourg

[Aaron Harrison]

Also (not too sure of the exact spec of your supervisor and the 6500 in general here, but this is true for other chassis switches) the ports of the supervisor are always true 1GB non-blocking ports, whereas ports on line cards can contend for bandwidth on the backplane... e.g. on a 4500 8-port card you may only have 6GB available on the backplane...

So it's better to have your uplinks non-blocking in my opinion..

Aaron

[Kevin Dorrell]

I've just thought of another argument for putting the uplinks on the supervisor card. If you have a power supply fault and the surviving power supplies are not enough to power the whole chassis, then the switch will power down line cards until they are within the power budget. The last one to go is the supervisor card. If your uplinks are on line cards, then the switch might not be able to report (syslog, SNMP) what it wrong, which would add to the repair time.

Kevin Dorrell

Luxembourg