Layer 3 Switch using OpenFlow - Routing in Hardware for IPv4 and IPv6

[Anonymous]

Hello,

when I look at pages 68 onwards of the OpenFlow Administrators guide[1] it looks to me that HP switches currently might or might not route IPv4 in hardware using OpenFlow. The Administrator guide says that they can read all necessary fields in hardware but at the same time for some models it seems to be impossible to set the DST MAC which would be necessary also they don't say anything about the decrementation of TTL and recalculate the IPv4 header checksum, however if you search the document it looks like this can be done in hardware. Could someone shed some light into that?

For IPv6 I'm pretty sure that HP switches currently can't route in hardware simply because it is not possible to match

the destination IPv6 address in hardware. Can someone confirm this?

Cheers,

      Thomas

[1] http://goo.gl/B4ngdh

[LeoJH3]

Hi Thomas,

Thanks for your questions.

It is a fact that IPv4 routing cannot be done via OpenFlow in hardware on HP switches. The destination MAC address cannot be changed in hardware on some models and the decrement TTL is not supported in hardware via OpenFlow either. Many models of HP switches do support legacy IPv6 routing i.e. they have the ability to match the destination IPv6 address in hardware and route accordingly. However, the same cannot be accomplished via OpenFlow for the same reasons i.e. the inability to modify destination MAC address in some models and the inability to decrement TTL.

Please do let us know if you need any further assistance regarding this query. Please reply incase you have more questions around the same topic or open a new thread if new topic.

If you feel this isuses is resolved, please do let us know by marking response as an 'accepted solution’.

Thanks,

Leo
 

[Anonymous]

Hello Leo,

thank you for your answer. I assume that the above was for Provision based hardware. Do you have any insight on Comware. Especially I'm interested in the following:

- Does Comware based hardware allow to change the mac address and decrement the TTL in hardware?

- Can Comware based hardware match IPv6 src/dst address in hardware?

- Is there a timeline for TTL decrement/set hardware mac address for provision based hardware?

- Is there a timeline for hardware match IPv6 src/dst address in hardware for provision based hardware?

Cheers,

     Thomas

[LeoJH3]

Hi Thomas,

Got your new questions, will be working on finding you solutions and post back asap.

-Leo

[LeoJH3]

Hi Thomas,

Here's some feedback so far. Still working on the Comware questions.

3Q) Is there a timeline for TTL decrement/set hardware mac address for provision based hardware?

       3A) We appreciate the feedback but we cannot provide a timeline. The destination MAC address can be changed in hardware on some ProVision switches – 5400 and 8200 with v2 modules and the 3800.

4Q) Is there a timeline for hardware match IPv6 src/dst address in hardware for provision based hardware?

       4A) This is already supported on some ProVision switches – 5400 and 8200 with v2 modules, 3800 and the 2920.

-Leo

[Anonymous]

Hello Leo,

the documentation said that the Destination MAC can be changed, however in your post you said that the Destination MAC can not be changed the TTL of the IPv4 can not be decremented and the IPv4 Header chekcksum can not be recalculated in hardware. So can you confirm that for v2 hardware IPv4 and IPv6 can be matched in hardware (the documentation says that only IPv4 can be matched in hardware) and that for IPv4 and IPv6 the destination mac address can be set, the TTL (IPv4) or HOP Count (IPv6) can be decremented in hardware and the header checksum of IPv4 can be recalculated after changing the TTL in hardware?

I have to get my hands on a 3800 or buy one to verify the same by myself.

Cheers,

      Thomas

[LeoJH3]

Hi Thomas,

Thanks for the response.  I think there maybe a little misunderstanding, so I tried to break down some of your questions into more concise 'one liners'.  In the future it would be a great help if you could please format your questions in a similar fashion which would help us to get you a more timely and concise answer.  Also starting new threads for new topics would greatly help others to be able to search and find specific topics better.

1 . Set Mac address in hardware for IPV4/IPV6

The source MAC address can be modified in hardware on 2920, 3800, 5400 and 8200 with v2 modules.

The destination MAC address can be modified in hardware on 3800, 5400 and 8200 with v2 modules.

2.  Match Src/Dst address in hardware for IPv4/IPv6

Compatible switches: 2920, 3800, 5400 and 8200 with v2 modules.

3. Decrement TTL (IPv4) in hardware

None i.e. no switches support this via OpenFlow.

4. Decrement HOP Count (IPv6) in hardware

None i.e. no switches support this via OpenFlow.

Please note:

The OpenFlow match and action charts for hardware provide all this information in the Appendix section of the “OpenFlow Administrator’s Guide”. Unfortunately there is a documentation error in the description of the captions for the figures. We have asked that these be corrected but this has not been done yet. The correct captions should be as follows –

Figure 5 – pg 68

Existing text (incorrect)

OpenFlow v1.0 and v1.3 – K/KA.15.10 and K.KA.15.14 for 3500, 5400, 6200, 6600 and 8200 with v1 modules

Correct text (to be changed)

OpenFlow v1.0 – K.15.10 and K.15.14 for 3500, 6200, 6600, 5400 and 8200 with v1 modules

OpenFlow v1.3 – K.15.14 for 3500, 6200, 6600, 5400 and 8200 with v1 modules

Figure 6 - pg 69
Existing text (incorrect)
OpenFlow v1.0 – K/KA.15.10 and WB.15.12 for 2920, 3800, 5400 and 8200 with v2 modules
Correct text (to be changed)
OpenFlow v1.0 – K.15.10 for 5400 and 8200 with v2 modules, KA.15.10 for 3800 and WB.15.12 for 2920

Figure 7 - pg 70
Existing text (incorrect)
OpenFlow v1.3 - K/KA.15.14 for 3500, 5400, 6200, 6600 and 8200 with v1 modules and K/KA/WB.15.14 for 3800, 5400 and 8200 with v2 modules
Correct text (to be changed)
OpenFlow v1.0 and v1.3 – K.15.14 for 3500, 6200, 5400 and 8200 with v2 modules, KA.15.14 for 3800 and WB.15.14 for 2920
 

Still working on the Comware questions.

Hopefully this helps and answers your questions. If so, please close this thread and if you have any additional questions please let us know.

-Leo

[Anonymous]

Hello Leo,

thank you for your feedback. Most of it I already knew from the documenation. New for me was that the TTL/hopcount can not be decremented. But one question stays unanswered: Is it possible to match IPv6 IP addresses in hardware with v2 version?

Thank you for your effort to get to the bottom of this.

Cheers,

      Thomas

[LeoJH3]

Hi Thomas,

You're more than welcome.  I believe this question was answered previously but to clarify:

This is already supported on some ProVision switches – 5400 and 8200 with v2 modules, 3800 and the 2920.

Hope this helps!

If you feel we have answered your question, please let us know by marking this response as an 'accepted solution’.

Thanks,

Leo