Jellyfish

Question 1

a high-capacity network interconnect which, by adopting a random graph topology, yields itself
naturally to incremental expansion

Answer 1

Jellyfish

Question 2

more cost-efficient than a fat-tree,
supporting as many as 25% more servers at full capacity using the same equipment at the scale of a few thousand nodes, and this advantage improves with scale.

Answer 2

Jellyfish

Question 3

a degree-bounded2 random graph topology
among top-of-rack (ToR) switches. The inherently
sloppy nature of this design has the potential to
be significantly more flexible than past designs.

Answer 3

Jellyfish

Question 4

can support 25% more servers than a fattree
while using the same switch equipment and
providing at least as high bandwidth. This advantage
increases with network size and switch portcount.

Answer 4

Jellyfish

Question 5

The Jellyfish approach is to construct a
random graph at the top-of-rack (ToR) switch layer. Each ToR switch i has some number ki of ports, of which it uses ri to connect to other ToR switches, and uses the remaining ki ..ri ports for servers.

Answer 5

Jellyfish Topology

In this case, the network is a random
regular graph, which we denote as RRG(N, k, r).

Question 6

two key goals of Jellyfish

Answer 6

high bandwidth and

flexibility

Question 7

have high throughput because they have low average path length, and therefore do less work to deliver
each packet.

Answer 7

Random graphs

Question 8

a common measure of network capacity, is the

worst-case bandwidth spanning any two equal-size partitions of a network

Answer 8

Bisection bandwidth,

Question 9

allows for heterogeneous expansion

Answer 9

Jellyfish

Question 10

substantially more cost-effective than LEGUP’s Clos network expansion. With the same budget for equipment and rewiring at each expansion stage (x-axis), Jellyfish obtains significantly higher bisection bandwidth (y-axis). Results are averaged over 10 runs

Answer 10

Jellyfish’s incremental expansion

Question 11

highly resilient to failures:

Answer 11

Jellyfish
(Jellyfish topology is even more
resilient than the same-equipment fat-tree (which itself
is no weakling))

Question 12

performs poorly for Jellyfish,

not providing enough path diversity.

Answer 12

ECMP (equal cost multipath routing)

Question 13

exploits Jellyfish’s high capacity well

Answer 13

Simple k-shortest path forwarding with MPTCP

Question 14

represent a novel approach to the significant problems of incremental and heterogeneous expansion, while enabling high capacity, short paths, and resilience to failures and miswirings.

Answer 14

random graphs (Jellyfish)