One thing you've missed is 'what protocol'? While most routers are multiprotocol, a disturbing number of L3 switches are IP only. It's amazing how much 'not IP' is still out there and needs to be accounted for...
When I sit down with a customer, I usually try and ask questions that are more business specific. What are you using the network for today? What about tomorrow? Any plans on running Voice applications? Video? Storage Networking? Then I try to figure out what timeframe the customer is buying for - is this something for a particular project or immediate need and can be immediately discarded? Or is this something that has to last for a long time - and how long is long? And lastly - What is the budget? Even if a customer *needs* a BFR (big fast router) - if the budget is only $3000, some obvious compromises will need to be made. Only then does it make sense to dive into the technical details of flow rates, CPU usage, latency needs, etc. Frank Jimenez, CCIE #5738 Systems Engineer Cisco Systems, Inc. [EMAIL PROTECTED] -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of The Long and Winding Road Sent: Sunday, January 05, 2003 3:53 PM To: [EMAIL PROTECTED] Subject: On Topic Design Question - sizing a router or switch [7:60361] This one came up at the water cooler the other day. When going through the design process, what factors are useful for determining router and switch equipment requirements. In other words, how do I know when it is time to upgrade my router? Not numbers and types of ports, but what factors should be considered when determining if a router or switch will have sufficient horsepower to serve an organization's need for the purpose and time frame required. For example, if I were to determine that my requirement is ATM DS3, simple QoS ( for voice prioritization ) my non voice data will flow at 10 megabits peak on the WAN and typical flow of 3 megabits, and that my voice traffic will use G729 and end up with about 1 megabit average and 3 megabit peak. I can look at things like Cisco's published numbers on PPS, I can set up a test lab, simulate traffic flow, and check out CPU usage. I suppose if I were very sophisticated, I could measure throughput, latency, etc. I understand that as with all things networked, the answer is "it depends". things like access-lists, process switching, policy routing, etc can effect things. Some of us are just debating whether or not CPU utilization is the "best" measure. Over what period? What other factors might be best brought into the mix of factors to consider? Just wondering. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=60374&t=60374 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
