Dear BESS Experts
?? On NVO3 VXLAN overlay encapsulation
My understanding of VXLAN source port entropy is to provide uniform load
balancing similar to RFC 6437 IPv6 flow label uniform stateful load
balancing, in NVO3 VXLAN context, using header 5-tuple L2/L3/L4 hash and
generating source port input key to hash function for per packet per flow
uniform load balancing as achieved with EVPN ECMP pr weighted UCMP MHD
MLAG PE-CE AC.
The problem with L3 ECMP and weighed UCMP is the Day 1 well known TCP
polarization of flows where high bandwidth flows are not evenly distributed
between L3 paths.
So the question is does source port entropy provide per RFC 7348 excerpt
below provide per packet per flow load balancing or flow based where all
packets that are part of the same flow get hashed to the same path.
Outer UDP Header: This is the outer UDP header with a source port
provided by the VTEP and the destination port being a well-known
UDP port.
- Destination Port: IANA has assigned the value 4789 for the
VXLAN UDP port, and this value SHOULD be used by default as the
destination UDP port. Some early implementations of VXLAN have
used other values for the destination port. To enable
interoperability with these implementations, the destination
port SHOULD be configurable.
- Source Port: It is recommended that the UDP source port number
be calculated using a hash of fields from the inner packet --
one example being a hash of the inner Ethernet frame's headers.
This is to enable a level of entropy for the ECMP/load-
balancing of the VM-to-VM traffic across the VXLAN overlay.
When calculating the UDP source port number in this manner, it
is RECOMMENDED that the value be in the dynamic/private port
range 49152-65535 [RFC6335
<https://datatracker.ietf.org/doc/html/rfc6335>].
Kind Regards
Gyan
--
<http://www.verizon.com/>
*Gyan Mishra*
*Network Solutions A**rchitect *
*Email gyan.s.mis...@verizon.com <gyan.s.mis...@verizon.com>*
*M 301 502-1347*
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