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New Member

Supervisory engine, backplane switching,line cards

Hello,

i have a couple of questions and they are thus:

1.Is the line card a module or are they different parts of the switch. What is the function of the line card ?

2.From my understanding the supervisory engine is like the brain of the device. It controls all or most of the software related functionality of the device. Am I correct?

3.What is the difference between the SUP720 and SUP32?

4.Is the CatOS solely for layer 2 switching while the IOS is for routing?

5. when we refer to backplane does that mean how fast a switch switches packets ?

Best Regards,

DJ.

3 ACCEPTED SOLUTIONS

Accepted Solutions
Cisco Employee

Supervisory engine, backplane switching,line cards

Hello,

Please find below answers inline,

1.Is the line card a module or are they different parts of the switch. What is the function of the line card ?

Yes, Linecards/Modules are different part of the switch. You can insert multiple cards into the Chassis. You can also have service moduels like Wism/FWSM/ACE

depends upon the business needs.

2.From my understanding the supervisory engine is like the brain of the device. It controls all or most of the software related functionality of the device. Am I correct?

Yes, Supervisor is the brain of the switch controls each function. A typical Supervisor consists of PFC which has TCAM L2/L3 Engines and RP/SP Processor and A replication engine (Hyperion) for Multicast. TCAM is the area where the RP/SP programmes the switch. There are multiple things that get programmed in TCAM like QoS/ACL/Netflow etc.

They have their respective hardware entries in the TCAM. If the entry is not found that is when the packet gets punted to CPU. If the linecard has a DFC on it then it can download the information from L2/L3 Engines from TCAM and switching gets fast as everytime the lookup happens in the Linecard instead of the Supervisor.

3.What is the difference between the SUP720 and SUP32?

SUp 32 : 32Gb backplane supporting hardware accelerated Layer 2 and 3, QoS and Security policies up to 15Mpps…

Sup 720: 720Gb backplane supporting hardware accelerated Layer 2 and 3, QoS and Security policies up to 400Mpps…

4.Is the CatOS solely for layer 2 switching while the IOS is for routing?

If you have a hybrid switch with CATOS/MSFC(IOS) CATos represents the switching part and MSFC represents the Routing part of the network.

5. when we refer to backplane does that mean how fast a switch switches packets ?

Backplane is used for communication between SUP - LC's.The area divided into three subsections,

1) D-bus - Used for data flow

2) R-bus - Used for result lookups

3) EOBC - Control communications like IPC/ScP which is helps the Supervisor to maintain the other line cards.

Depends on the line card the backplane can work in three different modes,

1) Flowthrough


Between non fabric modules and between a non fabric and a fabric enabled linecard

Throughput – 15 Mpps (@ 64 byte frames)

Bandwidth – 16 Gbps of bandwidth shared throughout

Data Bus frame size is variable; min of 4 cycles (64B Data) on the DBus for every frame +1 wait cycle

2) compact

When only ALL fabric enabled linecards in a chassis

Throughput – 30 Mpps (@ any frame size)

Bandwidth – 8 G CEF256; 20 G/channel CEF720

Data Bus frame size is constant (compact header); 2 cycles (32 B Data) on the DBus for every frame + no wait cycle

3) truncated

Between fabric linecards when a non fabric linecard is in the chassis.

Throughput – 15 Mpps (@ 64 byte frames); independent of frame size for CEF256 and CEF720

Bandwidth – 16 G shared for classic; 8 G per CEF256; 20 G/channel CEF720.

Data Bus frame size is variable; min of 4 cycles (64 Bytes Data) on the Data Bus for every frame.

Thanks,

Ricky Micky

*Rate Useful posts

Super Bronze

Re: Supervisory engine, backplane switching,line cards

Disclaimer

The  Author of this posting offers the information contained within this  posting without consideration and with the reader's understanding that  there's no implied or expressed suitability or fitness for any purpose.  Information provided is for informational purposes only and should not  be construed as rendering professional advice of any kind. Usage of this  posting's information is solely at reader's own risk.

Liability Disclaimer

In  no event shall Author be liable for any damages whatsoever (including,  without limitation, damages for loss of use, data or profit) arising out  of the use or inability to use the posting's information even if Author  has been advised of the possibility of such damage.

Posting

To possibly clarify or expand on what Ricky posted.

2. From my understanding the supervisory engine is like the brain of the  device. It controls all or most of the software related functionality of  the device. Am I correct?

Yes, although some 6500 line cards support DFCs, which make local forwarding decisions on the line card itself.  Some 6500 service module line cards run pretty autonomously, i.e. they don't rely much on the main supervisor.

3.What is the difference between the SUP720 and SUP32?

The latter only supports "classic bus" and supervisor forwarding.  There's a variant of the latter that also supports deep packet inspection.

The former also supports/provides a fabric and supports line cards with DFCs. There's also a variant of the former that allows two individual chassis to operate as a single device.

The former is also more expensive than the latter.

4.Is the CatOS solely for layer 2 switching while the IOS is for routing?

Historically, CatOS was for Catalyst switches, which with the right platform did support routing in "hybred" mode.  Historically, IOS was for Cisco routers.

Currently, IOS is used on both switches and routers, and for L3 switches, IOS supports routing in "native" mode (along with switching).  CatOS is, more or less, depreciated.

5. when we refer to backplane does that mean how fast a switch switches packets ?

No, its more of a generic reference of what "glues" together system components.  Originally it often was the back of the chassis which line cards slid into which connected them electrically, also often a common bus.  Since the backplane's circuitry is often what allows different components to communicate, it's capacity, or lack there of, can limit how fast packets can be switched but there are many other factors for determining, overall, how fast a switch can switch packets.

Hall of Fame Super Gold

Re: Supervisory engine, backplane switching,line cards

1.Is the line card a module or are they different parts of the switch. What is the function of the line card ?

Main objective of the line card is to allow users to "customize" what they want with their chassis-based switch system.  You want a 48-port card with 1Gb RJ and no PoE for slot 1?  And for slot 2 you want a different variety of line card?  How about slot 7 do you want an ACE?

2.From my understanding the supervisory engine is like the brain of the device. It controls all or most of the software related functionality of the device. Am I correct?

It is THE brain.  Without a supervisor card the chassis is just a big piece of door jam.  Nowadays, chassis-based systems can and will operate with dual Supervisor card.

3.What is the difference between the SUP720 and SUP32?

As stated, the Sup32 will support up to 32 Gb while the Sup720 will support up to 720 Gb.  The new card, Sup2T will support up to 2 Tb.  The value is computed in HALF Duplex.  The price of the Sup2T and the Sup720 are the same so it's worthwhile investing in the newer Sup2T.

Now, in the past and before Sup2T was released, Cisco recommended the Sup32 as an access switch (Sup32 was NEVER intended to be a core switch because it does not have enough bandwidth and this the reason why the line cards that will operate under the Sup32 are limited) or the 4500R+E and Sup7E and the Sup720 to be the distro and/or core switch.  After the release, the recommendation was ammended that the Sup720 retains as the distro while the Sup2T is now positioned as a (super) core switch.

7 REPLIES
Cisco Employee

Supervisory engine, backplane switching,line cards

Hello,

Please find below answers inline,

1.Is the line card a module or are they different parts of the switch. What is the function of the line card ?

Yes, Linecards/Modules are different part of the switch. You can insert multiple cards into the Chassis. You can also have service moduels like Wism/FWSM/ACE

depends upon the business needs.

2.From my understanding the supervisory engine is like the brain of the device. It controls all or most of the software related functionality of the device. Am I correct?

Yes, Supervisor is the brain of the switch controls each function. A typical Supervisor consists of PFC which has TCAM L2/L3 Engines and RP/SP Processor and A replication engine (Hyperion) for Multicast. TCAM is the area where the RP/SP programmes the switch. There are multiple things that get programmed in TCAM like QoS/ACL/Netflow etc.

They have their respective hardware entries in the TCAM. If the entry is not found that is when the packet gets punted to CPU. If the linecard has a DFC on it then it can download the information from L2/L3 Engines from TCAM and switching gets fast as everytime the lookup happens in the Linecard instead of the Supervisor.

3.What is the difference between the SUP720 and SUP32?

SUp 32 : 32Gb backplane supporting hardware accelerated Layer 2 and 3, QoS and Security policies up to 15Mpps…

Sup 720: 720Gb backplane supporting hardware accelerated Layer 2 and 3, QoS and Security policies up to 400Mpps…

4.Is the CatOS solely for layer 2 switching while the IOS is for routing?

If you have a hybrid switch with CATOS/MSFC(IOS) CATos represents the switching part and MSFC represents the Routing part of the network.

5. when we refer to backplane does that mean how fast a switch switches packets ?

Backplane is used for communication between SUP - LC's.The area divided into three subsections,

1) D-bus - Used for data flow

2) R-bus - Used for result lookups

3) EOBC - Control communications like IPC/ScP which is helps the Supervisor to maintain the other line cards.

Depends on the line card the backplane can work in three different modes,

1) Flowthrough


Between non fabric modules and between a non fabric and a fabric enabled linecard

Throughput – 15 Mpps (@ 64 byte frames)

Bandwidth – 16 Gbps of bandwidth shared throughout

Data Bus frame size is variable; min of 4 cycles (64B Data) on the DBus for every frame +1 wait cycle

2) compact

When only ALL fabric enabled linecards in a chassis

Throughput – 30 Mpps (@ any frame size)

Bandwidth – 8 G CEF256; 20 G/channel CEF720

Data Bus frame size is constant (compact header); 2 cycles (32 B Data) on the DBus for every frame + no wait cycle

3) truncated

Between fabric linecards when a non fabric linecard is in the chassis.

Throughput – 15 Mpps (@ 64 byte frames); independent of frame size for CEF256 and CEF720

Bandwidth – 16 G shared for classic; 8 G per CEF256; 20 G/channel CEF720.

Data Bus frame size is variable; min of 4 cycles (64 Bytes Data) on the Data Bus for every frame.

Thanks,

Ricky Micky

*Rate Useful posts

Super Bronze

Re: Supervisory engine, backplane switching,line cards

Disclaimer

The  Author of this posting offers the information contained within this  posting without consideration and with the reader's understanding that  there's no implied or expressed suitability or fitness for any purpose.  Information provided is for informational purposes only and should not  be construed as rendering professional advice of any kind. Usage of this  posting's information is solely at reader's own risk.

Liability Disclaimer

In  no event shall Author be liable for any damages whatsoever (including,  without limitation, damages for loss of use, data or profit) arising out  of the use or inability to use the posting's information even if Author  has been advised of the possibility of such damage.

Posting

To possibly clarify or expand on what Ricky posted.

2. From my understanding the supervisory engine is like the brain of the  device. It controls all or most of the software related functionality of  the device. Am I correct?

Yes, although some 6500 line cards support DFCs, which make local forwarding decisions on the line card itself.  Some 6500 service module line cards run pretty autonomously, i.e. they don't rely much on the main supervisor.

3.What is the difference between the SUP720 and SUP32?

The latter only supports "classic bus" and supervisor forwarding.  There's a variant of the latter that also supports deep packet inspection.

The former also supports/provides a fabric and supports line cards with DFCs. There's also a variant of the former that allows two individual chassis to operate as a single device.

The former is also more expensive than the latter.

4.Is the CatOS solely for layer 2 switching while the IOS is for routing?

Historically, CatOS was for Catalyst switches, which with the right platform did support routing in "hybred" mode.  Historically, IOS was for Cisco routers.

Currently, IOS is used on both switches and routers, and for L3 switches, IOS supports routing in "native" mode (along with switching).  CatOS is, more or less, depreciated.

5. when we refer to backplane does that mean how fast a switch switches packets ?

No, its more of a generic reference of what "glues" together system components.  Originally it often was the back of the chassis which line cards slid into which connected them electrically, also often a common bus.  Since the backplane's circuitry is often what allows different components to communicate, it's capacity, or lack there of, can limit how fast packets can be switched but there are many other factors for determining, overall, how fast a switch can switch packets.

Hall of Fame Super Gold

Re: Supervisory engine, backplane switching,line cards

1.Is the line card a module or are they different parts of the switch. What is the function of the line card ?

Main objective of the line card is to allow users to "customize" what they want with their chassis-based switch system.  You want a 48-port card with 1Gb RJ and no PoE for slot 1?  And for slot 2 you want a different variety of line card?  How about slot 7 do you want an ACE?

2.From my understanding the supervisory engine is like the brain of the device. It controls all or most of the software related functionality of the device. Am I correct?

It is THE brain.  Without a supervisor card the chassis is just a big piece of door jam.  Nowadays, chassis-based systems can and will operate with dual Supervisor card.

3.What is the difference between the SUP720 and SUP32?

As stated, the Sup32 will support up to 32 Gb while the Sup720 will support up to 720 Gb.  The new card, Sup2T will support up to 2 Tb.  The value is computed in HALF Duplex.  The price of the Sup2T and the Sup720 are the same so it's worthwhile investing in the newer Sup2T.

Now, in the past and before Sup2T was released, Cisco recommended the Sup32 as an access switch (Sup32 was NEVER intended to be a core switch because it does not have enough bandwidth and this the reason why the line cards that will operate under the Sup32 are limited) or the 4500R+E and Sup7E and the Sup720 to be the distro and/or core switch.  After the release, the recommendation was ammended that the Sup720 retains as the distro while the Sup2T is now positioned as a (super) core switch.

New Member

Re: Supervisory engine, backplane switching,line cards

hello,

Thanks alot for all the clarifications, my doubts and queries have reasonable been put to rest now. As a request could i get links for further documentation on the questions i asked and is there a cisco modules do the three headings, supervisory engine, line cards and backplane fall into so I can further read on it more?

Regards,

DJ

Super Bronze

Re: Supervisory engine, backplane switching,line cards

Disclaimer

The   Author of this posting offers the information contained within this   posting without consideration and with the reader's understanding that   there's no implied or expressed suitability or fitness for any purpose.   Information provided is for informational purposes only and should not   be construed as rendering professional advice of any kind. Usage of  this  posting's information is solely at reader's own risk.

Liability Disclaimer

In   no event shall Author be liable for any damages whatsoever (including,   without limitation, damages for loss of use, data or profit) arising  out  of the use or inability to use the posting's information even if  Author  has been advised of the possibility of such damage.

Posting

This reference, http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps708/prod_white_paper0900aecd80673385.html, won't answer all your questions, but it provides lots of interesting information about the 6500 and should help you better understand other documents.

New Member

Re: Supervisory engine, backplane switching,line cards

Thanks alot Joseph. I also stumbled across this link which was of immense

help to me

http://www.firewall.cx/cisco-technical-knowledgebase/cisco-switches/340-cisco-switches-catalyst-4507r-e.html.

Although it focused more on the 4500 switch.

BR,

DJ

On Fri, Dec 16, 2011 at 12:31 PM, JosephDoherty <

New Member

Re: Supervisory engine, backplane switching,line cards

Please see http://www.cisco.com/en/US/products/hw/switches/ps708/prod_models_comparison.html which will provide you side by side comparison of 6500 supervisors and line card options.

Hope this helps!

_dschlicht

Sent from Cisco Technical Support iPad App

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