As you have sup 720 which has integrated SFM and also the line cards (WS-X6748-SFP & WS-X6748-GE-TX) which you are having is fabric enabled which means you have non blocking architecture setup and it will be operational at maximum port speed.
Actually, that is not correct. All of the 48 port Gig-E line cards for the 6500 are oversubscribed; it does vary by the degree of oversubscription.
In a 6506 or a 6509 (with a Sup720) you have (2) 20 Gbps connections (per slot) to the fabric. With a WS-X6748-GE-TX you have a potential for 48 (Full Duplex) Gbps of traffic, but only 2 connections to the fabric. This yields an oversubscription rate of 1.2:1 (or 48:40) assuming a worst case scenario.
It should be noted that the 24 port 67xx cards are still oversubscribed as well, because they only have one connection to the fabric. There is a potential for 24 Gbps of traffic and only (1) 20 Gbps fabric connection, so it has an identical oversubscription rate.
By using only 24 of the 48 possible ports, depending on which ones you choose, you should be OK. But I do not know which ports use which fabric connection on the backplane, so I can't assist you in picking them.
It should be noted that in most environments it is unlikely every port will be a 100% utilized so the risk of dropping packets because of oversubscription is low.
With 64 byte packets a Gig-E connection can push 1,488,000 in each direction, so Full Duplex would be 2,976,000. That is a per port number. Just multiply that times the number of ports and you'll reach your 30Mpps pretty fast. Keep in mind that those numbers are a worst case scenario. You need to consider what your real world traffic is going to look like and run the numbers. Is it likely that your average packet size will be the smallest packet size? 30Mpps is a lot of traffic.
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...