[ovs-discuss] Port range matching

[Yaxuan]

Hi, Mike,
 </:includetail> 
 Although it is not difficult to implement Range-match on OvS, it is definitly a bad thing for hardware-based OpenFlow switches.</:includetail>
 </:includetail> 
 In the worst case, 1 range can expand to 2(W-1) prefixes, where W is the bit-width of a header field (e.g. W=16 for L4 port fields). So for the TCAM based hardware, it might waste many TCAM entries for a single rule. </:includetail>
 </:includetail> 
 I agree with supporting range-match on software vswitches, but keep only prefix on hardware switch.</:includetail>
 </:includetail> 
 </:includetail> 
 </:includetail> 
 Yaxuan</:includetail>
  
   
  ------------------ Original ------------------
  From:  "Mike Bursell"<mike.bursell at citrix.com>;
 Date:  Fri, Aug 5, 2011 08:31 PM
 To:  "discuss at openvswitch.org"<discuss at openvswitch.org>; 
 
 Subject:  [ovs-discuss] Port range matching

  
Hi -

I'm investigating the possibility of adding port range matching to
rules.  In other words, rather than just specifying a single tp_dst, you
could add a range.  In other words:

tp_dst = 8080-8083
would be equivalent to having four rules: with tp_dst 8080,8081,8082 &
8083. 

I'm not suggesting that we remove the existing support for a single
port, of course.

I was wondering whether this has been discussed before?  It seems like a
fairly obvious addition both to Open vSwitch and to OpenFlow.

Protocol changes would obviously be required.  We might, for example,
adding the following fields to ofp_match:

uint16_t tp_src_end /* TCP/UDP/SCTP source port range end. */
uint16_t tp_dst_end /* TCP/UDP/SCTP destination port range end. */

Given these changes, my initial feeling is that it shouldn't be too
difficult to add the matching to the vSwitch itself.  If the tp_*_end
wasn't set, then we could safely ignore it matching time.

Does anyone have any comments?  I know this isn't the place to discuss
protocol changes in detail, but I thought I'd bounce the idea of this
group, which I've heard is both friendly and responsive.  :-)

-Mike.
-- 
Mike Bursell, Network Subsystem Architect
Citrix Systems R&D.  +44 7971 926937
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