Monday, August 3, 2020

VPLS.US 10/24/2012 &

I was just asked the most interesting question.

is this question valid?
A computer with a host IP address of sends a data packet with a destination, IP address of A subnet mask of is being used. Determine whether the packet stays in the LAN or is sent to the gateway.

Of course any question is valid. But is it a good question, is probably a better question.

So that question “WAS” pretty simple in 1999. It stays on the “LAN” however that LAN could have been separated by as many as three layer 2 hops. So from a Layer 3 perspective they would be local to each other. Any traffic destined as described above wouldn’t have to go up to an intelligent device to “route” the traffic but it could be “switched” to it’s end destination. The traffic would not cross IP Broadcast domains, but could cross multiple collision domains, depending of if it was crossing a hub or a switch. But, I guess there probably aren’t any hubs around today.

So in the old days, it probably behaved like the question asker was asking.

today? Well maybe not so much. If that same set of devices were placed into a Virtual Private LAN Service that were spread between Los Angeles and London, and the one computer .1 arp’d to get the MAC address of the other computer
the .2 to send it a frame of data, the traffic would flow between California and London to get the physical MAC address of the .2 computer. All of that was “Officially” and technically to the letter of the question I suppose it would be on a LAN. However that LAN is spanning across North America and the Atlantic Ocean. That’s a pretty big freaking Broadcast domain.

Which really begs the question of a definition of a LAN anymore. does that really have a meaning? Is a Local Areal Network really spanning half way around the world? Does a LAN span around a city or state? What’s local now days?

It also calls into question something that Marion Evans and I talked about many times. He was always being factious but he would say “Let’s just make the whole world a big broadcast domain” He was implying about the poor design characteristics that were being employed on the pseudowire service that we were starting to roll out, looking ahead to the LAN service we were planning to roll out.

Probably not the best design practice, which is partially why I’ve always been of the opinion that at some point the WAN should pass through a router. I wouldn’t ever put a Switch on a VPLS. it really needs to make a Layer 3 hop so that some amount of Layer 3 intelligence can be used for directing the traffic as it leaves between a layer 2 domain and a Layer 3 domain.

Of course the question asker above could have been completely confused and not really understand the basic principles of the question they were asking? Technology is changing.

According to mercury news..

Juniper Networks reportedly for sale, shares in Sunnyvale company jump

I heard the rumor Monday, and then was checking around the web for more information. I’m trying to figure out if this is a tip and I should be buying JNPR shares or if this is just a rumor because of all the layoffs…

Juniper Networks shares jumped 11 percent Thursday after a news website said the Sunnyvale network gear maker had hired JP Morgan to evaluate possible bids, but a source close to the matter said there was no substance to the report.

Juniper’s shares jumped on Thursday morning as the report spread among investors, hitting a one-month high of $19.20 on the New York Stock Exchange before easing back to $18.

One bid is reported to be in the high $20s per share with data storage firm EMC mentioned recently as a potential buyer, reported late on Tuesday.

However, getting past the profit part of it (For me of course), would a EMC/JNPR merger make sense? Well with the recent development work that JNPR has done with the Qfabric, and EMC has recently certified the qfabric to work with their gear.

What does that mean? Well juniper is a 9 billion dollar company and EMC is a 53 Billion dollar company, or roughly 6times the size of JNPR. That’s not insignificant. They could buy them for the qfabric and spin the rest off as a small router company. Or they could keep the whole company, much as Brocade did when they purchased Foundry. That particular deal made a lot of sense, it gave brocade all the networking technology it needed and also let if have the cheaper data center switches without “partnering” with another networking company. If EMC had their own switching division. They might be able to go after total deals, rather than just going after the host and data services. They could go in with a complete soup to nuts solution with firewall and routing capabilities. That has to look attractive.

Well, shares look expensive today? $17.19
Maybe tomorrow.

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