Sup 32 PISA vs 720

Unanswered Question
Aug 23rd, 2007

I have to compare both these supervisors for a client

1) Sup 32 PISA provides for NBAR in hardware to limit bandwidth to P2P apps, skype, etc. However, they are currently using a proxy for internet service and plan to continue doing so and all these protocols are disallowed. Hence, I don't see a benefit there

2) They plan to implement VOIP on the network. Can someone stress on what benefits the PISA would provide over the 720 here?

3) The client also plans to use ACL's on VLAN SVI's and I think 720 does an equally good job as the PISA would. I may also provide the option of the FWSM and they can choose.

Apart from the ones I've mentioned, are there any considerations I should be making to choose the PISA over 720 with the assumption that the client wants to provide for the future hence a beefier backplane would suit better, budget not being a consideration.

I have this problem too.
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Joseph W. Doherty Thu, 08/23/2007 - 10:19

The last point you touched on, backplane, is an important difference; as is maximum forwarding performance. The sup32 PISA is still a "classic bus" design and rated at 15 Mpps (roughly 10 Gbps with 64 byte packets), while the sup720 provides a fabric connection of either 20 or 40 Gbps per slot and allows DFCs on the line cards (that support them) to provide up to 400 Mpps within the chassis. The deep packet inspection is noted as 2 Gbps for the sup32 PISA; not available on the sup720.

From a performance standpoint, the sup32 PISA might be ideal for the user edge, "iffy" for distribution or server edge, and likely not the best choice for core.

ciscors Mon, 08/27/2007 - 07:10

Got it. Thanks

In terms of access lists, do you know if L3 ACL'S & VACL's are switched in hardware on either of the supervisors and if one has an advantage over the other for this functionality?


Joseph W. Doherty Mon, 08/27/2007 - 11:52

Discounting the fabric advantages or DFC support of the sup720, my understanding would the supervisors would be on par for "traditional" L3 ACLs & VACLs. Where the PISA comes into its own if you want to do NBAR (network-based application recognition) or FPM (flexible packet matching).

The PISA appears very attractive where you want the capability to deeply analyze traffic. The sup720 has more potential power for traditional switching/routing.

For a possible "ideal" design, PISA sups would be on the edges where you need the initial traffic analysis, and behind them, the sup720s. I'm guessing your facing an "either or" and not a "can use both" issue. If so, this is a tough call especially since the choice will also impact line cards.

If the choice was just between the original sup32 and sup720, then it's much simpler. Since the sup32-PISA is on the table, assume someone considers what it offers important.

What you might consider, if you can not do both (PISA and sup720), is something like a PISA on the edge with something other than the sup720 on the inside, such as a 4948, 3560-E or 3750-E.


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