Abstract:
A virtualized data center is highly multifarious environment, shared among hundreds
of co-located tenants hosting heterogeneous applications. High degree of virtual machine
consolidation leads to diverse tra c dynamics with uneven tra c demands.
Tenants' virtual machines generate a subset of elephants or mice
ows that traverse
the underlay fabric in aggregate, i.e., encapsulated in tunneling protocols such as
VXLAN, NVGRE and STT. Elephant
ows are long-lived and bandwidth intensive
whereas mice
ows are short-lived, latency-sensitive and highly bursty in nature.
Both types of
ows require di erent treatment from underlay fabric but encapsulation
obfuscates the overlay tra c characteristics and demands. Existing approaches
employed in data centers such as ECMP are either agnostic to elephant and mice
ows or have no visibility into virtual tra c which may be used to precisely detect,
isolate and treat elephant
ows di erently than mice
ows. If elephant
ows are
not identi ed and addressed in aggregated virtual tra c, they may a ect mice
ows
generated from co-located applications, hence degrading application performance of
co-located tenants. Therefore, there is a need to manage virtual tra c along with
physical tra c in data centers. This work identi es and treats elephant
ows belonging
to di erent tenants on virtual network components such as virtual switches
residing in the hypervisor. Virtual switch is at the optimal location to detect and
handle elephant
ows before they saturate the underlay network fabric and may be
used to ameliorate the network performance with minimal overhead both on host and
in-network. The proposed scheme has been tested against state of the art approaches
such as Hedera and ECMP and has shown improved bisection bandwidth on a 4-array
fat-tree interconnect.
