How to build a 100,000-port Ethernet switch

[SYNACK]

Ever want bigger switches and the ability to run all hosts on a single subnet without performance degredation. So did some researchers who have devised a way to make layer 2 switchind scale well beyond current barriers.

University of California researchers are presenting a paper describing software that they say could make data center networks massively scalable. The researchers say their PortLand software will enable Layer 2 data center network fabrics scalable to 100,000 ports and beyond, and they even have a prototype running at the school’s Department of Computer Science and Engineering’s Jacobs School of Engineering.

This inclueds a system that uses psudo MAC addresses to remove almost all of the nasty broadcasts that choke current networks at this scale.

How to build a 100,000-port Ethernet switch - Network World

The question is: How do you rackmount a 42u switch?

[laserblazer]

Why not just daisychain 14,000 odd 8-port switches?

[SYNACK]

Why not just daisychain 14,000 odd 8-port switches?

Assuming that this is a genuine question the answers are manyfold:
Even with 48 port switches the ammount of interconnects required to get that may ports would seriously limit bandwidth and use up vast amounts of hardware simply to connect the switches together. I don't expect that the above system would be imune to this either as 100,000 ports would need a lot of bits of hardware spread over many cabinets but it would be structured better.

Given the number of required interlinks to connect all of this gear you could end up with 100 or more hops end to end meaning huge hardware delay (comparitivly) as the whole ethernet stack is implemented on each device along with conversion delays to fibre and back etc.

The main issue that crushes all of these is the broadcast domain that would be created. Each time a host needs to resolve an ip address to a name that is not in a different subnet or get dhcp information or run any number of protocols that include broadcasts these are sent to every port on every connected switch. In networks of around 500 hosts this starts to make a noticable impact on performance as the broadcasts make up a large percentage of the traffic. Scaleing that up the network simply becomes unuseable because all of the bandwitch is used by broadcasts bouncing about.

Each connected host also reads every single broadcast frame (in CPU unless it is a top end NIC) which means that every client is constantly being bombardes with CPU interupts slowing the even the clients to a crawl. This is one reason why network loops that cause broadcast storms can slow down older clients as well as killing the network. Imagine the same scenario without the loopback or any way to solve it other than resorting to layer 3 IP routing.

Hope that adds a little clarity to my earlier post

[AngryTechnician]

The question is: How do you rackmount a 42u switch?

With a 42U cabinet, a forklift, 4 cage nuts, and a PZ2 screwdriver.

[dhicks]

Ever want bigger switches and the ability to run all hosts on a single subnet without performance degredation. So did some researchers who have devised a way to make layer 2 switchind scale well beyond current barriers.

Darn it, I know I sat through a presentation about this a few weeks ago, but I can't remember the name of the company who were doing it now. I'll try and remember.

--
David Hicks

[K.C.Leblanc]

The question is: How do you rackmount a 42u switch?

Step 1, stab your self in the hand while installing the captive bolts.

Step 2, After launching several bolts into a dusty void below the cabinet discover you are now one short.

[AngryTechnician]

Step 1, stab your self in the hand while installing the captive bolts.

Step 2, After launching several bolts into a dusty void below the cabinet discover you are now one short.

That 100% accurately describes my first rackmounting experience several years ago.

[Michael]

The question I have to ask is where is there demand for a 100,000 port switch?

[ahuxham]

The question I have to ask is where is there demand for a 100,000 port switch?

I can think of a few, specifically Military Manufacturing Installations

[K.C.Leblanc]

The question I have to ask is where is there demand for a 100,000 port switch?

It's one big trunk port feeding into Geoff's brain.

[ahuxham]

It's one big trunk port feeding into Geoff's brain.

Not enough ports!

[Michael]

I'm sure Geoff has a big brain, but still, that's a lot of ports even for the Military!

Working on the presumption you have a 48 port switch, 48 port patch panel and a cable tidy which would use 3u = 16 x 48 port switches.

48 x 16 = 768 ports
100,000 / 768 ports = 130 x 42u cabinets

[SYNACK]

The question I have to ask is where is there demand for a 100,000 port switch?

I'm sure Geoff has a big brain, but still, that's a lot of ports even for the Military!

Working on the presumption you have a 48 port switch, 48 port patch panel and a cable tidy which would use 3u = 16 x 48 port switches.

48 x 16 = 768 ports
100,000 / 768 ports = 130 x 42u cabinets

Yes it is a lot of ports but if you read the article it does say that the intended market is large datacenters that could easily use that much connectivity along with about the same amount of power as a small city no doubt