Sup2(6500 or 7600) is not demand-based, there is no flow-based forwarding on it; it can actually go that far, but you are right about past (and most of current) Cisco claims. In order to have 30 Mpps inside 15Gbps traffic, packet size on the line would be 62.5 bytes and no silence between packets would be allowed. When preambles and inter-frame-gaps are included, bottom line traffic would be higher, and real packet size distribution would make it usable for up to lot more traffic. As this thread was started by ACL issues, are the 50/90/150 Mpps boxes you mentioned capable of ACLs at these line rates ? What other beasts besides IP II, Sup2, Eng 3 and Eng4/edge can handle high-rate ACLs ? Rubens Kuhl Jr. -----Original Message----- From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu] On Behalf Of Pete Kruckenberg Sent: Friday, October 19, 2001 3:44 PM To: nanog@merit.edu Subject: RE: 12000 ACL issue On Fri, 19 Oct 2001, Rubens Kuhl Jr. wrote:
Why do you think 6500/7600 doesn't have the required performance ? 30 Mpps Sup 2 with fabric-enabled line-cards can perform incredibly well... Having FlexWAN and other non-fabric line-cards will slow down to 15 Mpps, which is usually enough. VLAN L3 interfaces are required only on CatOS (which is today required by POS modules, unfortunately), but not on Supervisor IOS.
Those are advertised numbers, best-case assuming flows that can be distributed away from the MSFC. My experience with Cisco in the past is they rarely get close to advertised numbers, YMMV. Not that even 30Mpps (15Gb/s) is adequate for a GigE aggregation device, and 15Mpps (7Gb/s) is not enough. Even then, other vendors are advertising on the order of 50-90Mpps in the same size chassises, and at least in my lab they are achieving that. For the same price or less than 6500, lots less than 7600. And larger chassises are avaiable doing on the order of 150Mpps. In my experience, service providers that are doing lots of L3 GigE are not using 6500's or other Cisco products, at least for GigE services. 6500 is still strong in the L2 GigE space. With 10GigE, Cisco is even less appealing. SONET is a different story, of course. Pete.
-----Original Message----- From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu]On Behalf Of Rubens Kuhl Jr.
Sup2(6500 or 7600) is not demand-based, there is no flow-based forwarding on it; it can actually go that far, but you are right about past (and most of current) Cisco claims.
Please consult your favorite knowledgeable Cisco employee and try again. Understanding the 6500/7600 product matrix and its effects on forwarding tables is a pain - but required knowledge for successful implementation. There is a reason why CEF is configurable, and the DFC is an optional "card".
In order to have 30 Mpps inside 15Gbps traffic, packet size on the line would be 62.5 bytes and no silence between packets would be allowed. When preambles and inter-frame-gaps are included, bottom line traffic would be higher, and real packet size distribution would make it usable for up to lot more traffic.
Actually 30 Mpps comes from how the 6500/7600's data bus works - 256 bits wide @ 62.5 Mhz = 16 Gbps (real numbers - Cisco states 32 Gb/s due to their creative accounting). 64 Byte frame takes 4 clock cycles (64ns) to get through the box (at minimum). With that you get 15 Mpps. That is base functionality - add x-bars, DFCs, x-bar enabled cards, etc, etc, and YMMV. But regardless.. the larger the frame the smaller the number of pps.
As this thread was started by ACL issues, are the 50/90/150 Mpps boxes you mentioned capable of ACLs at these line rates ? What other beasts besides IP II, Sup2, Eng 3 and Eng4/edge can handle high-rate ACLs ?
There are many vendors in the world that do line rate ACLs those speeds. I believe one vendor showed off 172mpps with ACLs at a tradeshow recently. Think it was about 50% of the cost of a 6500 also. But I could be wrong. .chance
Sup2(6500 or 7600) is not demand-based, there is no flow-based forwarding on it; it can actually go that far, but you are right about past (and most of current) Cisco claims.
Please consult your favorite knowledgeable Cisco employee and try again.
As an early adopter and victim of 6500, the need for survival find the way to knowledgeable Cisco employees and knowledgeable admins/architets of networks with their own (different) paths to Cisco internals.
Understanding the 6500/7600 product matrix and its effects on forwarding tables is a pain - but required knowledge for successful implementation.
The product matrix today is rather simple: use Sup1 only for L2 activity (Consider Sup2 if you want VLAN ACLs and QoS), use Sup2 for all L3 activity, consider x-bar if you need more than 15 Mpps, consider DFC if you need more than 30 Mpps. Understanding the forwarding process of a device is crucial to network engineering; for instance, with 6500/7600 you should look carefully at the non-equal traffic distribution among parallel paths. With an M-160, you should try avoiding packet misordering, and so forth for every product of every vendor.
There is a reason why CEF is configurable, and the DFC is an optional "card".
CEF is mandatory with Sup2, and was with Sup1 although MLS took most of CEF pros and cons out of the loop.
In order to have 30 Mpps inside 15Gbps traffic, packet size on the line would be 62.5 bytes and no silence between packets would be allowed. When preambles and inter-frame-gaps are included, bottom line traffic would be higher, and real packet size distribution would make it usable for up to lot more traffic.
Actually 30 Mpps comes from how the 6500/7600's data bus works - 256 bits wide @ 62.5 Mhz = 16 Gbps (real numbers - Cisco states 32 Gb/s due to their creative accounting). 64 Byte frame takes 4 clock cycles (64ns) to get through the box (at minimum). With that you get 15 Mpps. That is base functionality - add x-bars, DFCs, x-bar enabled cards, etc, etc, and YMMV. But regardless.. the larger the frame the smaller the number of pps.
Not in the x-bar system (Sup2, switch fabric, all x-bar enabled cards), where Sup2 receives only the packet header (up to the point of L4 port info); this compressed mode of operation is required to achieve 30 Mpps. The same strategy is used on M- routers, where IP II receives only the first J-cell of the packet.
As this thread was started by ACL issues, are the 50/90/150 Mpps boxes you mentioned capable of ACLs at these line rates ? What other beasts besides IP II, Sup2, Eng 3 and Eng4/edge can handle high-rate ACLs ?
There are many vendors in the world that do line rate ACLs those speeds. I believe one vendor showed off 172mpps with ACLs at a tradeshow recently. Think it was about 50% of the cost of a 6500 also. But I could be wrong.
I really would like to see those products and review their architetures. So far, what I saw in every product except those above was: - Demand-based forwarding, where the first packet of a flow goes to the "processor-path"; - Processor-based ACLs, where L3 forwarding with no ACLs go "ASIC-path" and ACLs go "processor-path". Rubens Kuhl Jr.
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Rubens Kuhl Jr.