[mpls] draft-villamizar-mpls-tp-multipath

[Yong Lucy <[e-mail]>]

Hi Curtis,

 

Thank you for summarizing hashing based multipath solution in this draft.
Share my opinion here.

   

Draft Text:

 

   An alternate simple multipath technique uses a table

   generally with a power of two size, and distributes the table entries

   proportionally among component links according to the capacity of

   each component link.

 

   An adaptive multipath technique is one where the traffic bound to

   each component link is measured and the load split is adjusted

   accordingly.   

 

End Text

 

Comment:

1) Adjusting load over component link may cause flow reordering. 

2) If a huge amount of micro flows mix with few large and long live flows,
the load per entry can be out of balance

3) Measure component link load does not provide the info. for table entry
mapping adjustment

 

Internet traffic pattern today is different from decade or more years ago.
Hashing works well under the condition 

1) # of flows is very large and flow IDs are statistically random; 2) flow
BWs are pretty balanced. 

 

Otherwise, hashing has a trouble to make even load balance.  Hashing +
bucket mapping brings a room to deal with the unbalance if each bucket load
is measured. 

 

If the equipment understands flows better rather than just flow ID, more
proactive way can apply to multipath load balance. This is why we suggest
having large flow classification (draft-yong-pwe3-lfc-fat-pw-01)

 

Regards,

Lucy