VPLS.US

is this question valid?
A computer with a host IP address of 10.10.5.1 sends a data packet with a destination, IP address of 10.10.5.2. A subnet mask of 255.255.255.0 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.

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838
2012-10-24 16:36:30
2012-10-24 23:36:30
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10-45-10-2-10-45-10-3-24
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is this question valid?
A computer with a host IP address of 10.10.5.1 sends a data packet with a destination, IP address of 10.10.5.2. A subnet mask of 255.255.255.0 is being used. Determine whet ...]]>


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A Juniper spokesperson declined to give specific information about the divisions to be affected by the layoffs, or when they will happen. In an emailed statement, the spokesperson wrote: “As we disclosed on our second quarter 2012 earnings conference call, Juniper is working to align its resources to improve productivity and effectiveness, enabling us to deliver our road-map for innovation and unprecedented value to customers and shareholders. As a result of this important initiative, we are reducing our workforce by approximately 500 people in functions across the company.”

Juniper also declined to address the QFabric rumor directly. “Innovation is the lifeblood of Juniper,” the Juniper spokesperson said. “We’ve consistently achieved the highest overall market growth in Ethernet switching, and customers continue to adopt QFabric. We are focused on delivering innovative solutions in the data center that drive revenue for customers.”

So corrections in the direction. It had to happen. If you only build a product and you build it so large nobody buys it, you cannot afford to continue to make it. I know they were coming out with smaller qfabric boxes and they have already hit the street, but I imagine you had a huge work force basically sitting around twitting their thumbs while the smaller boxes are just a subset of a larger box, probably not a lot to do, plus there wasn’t any revenue coming in while the smaller boxes were being built. A serious strategy error.]]>

810
2012-10-07 19:31:33
2012-10-08 02:31:33
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jnpr-qfabric
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it's viable for maybe 2 companies in the world....

A Juniper spokesperson declined to give specific information about the divisions to be affecte ...]]>


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Of course it's in french. But if you translate it...

https://noc.sara.nl/nrg/dot1ag-utils/

bash-4.2# ethping -ieth1 -l7 -c5 00:00:5e:00:01:14
Sending CFM LBM to 00:00:5e:00:01:14
Request timeout for 1878795604
Request timeout for 1878795605
Request timeout for 1878795606
Request timeout for 1878795607
bash-4.2#

and a try with the trace


bash-4.2# ethtrace -i eth1 -l 7 00:09:3d:13:f2:a0
Sending CFM LTM probe to 00:09:3d:13:f2:a0
ttl 1: LTM with id 1925342007
no replies for LTM 1925342007
ttl 2: LTM with id 1925342008
no replies for LTM 1925342008
ttl 3: LTM with id 1925342009
no replies for LTM 1925342009
ttl 4: LTM with id 1925342010
no replies for LTM 1925342010
ttl 5: LTM with id 1925342011
no replies for LTM 1925342011
ttl 6: LTM with id 1925342012
no replies for LTM 1925342012
ttl 7: LTM with id 1925342013
no replies for LTM 1925342013
ttl 8: LTM with id 1925342014
no replies for LTM 1925342014
ttl 9: LTM with id 1925342015
no replies for LTM 1925342015


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780
2012-09-30 11:07:58
2012-09-30 18:07:58
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odds-ends
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http://www.bortzmeyer.org/ethernet-oam.html

Of course it's in french. But if you translate it...

https://noc.sara.nl/nrg/dot1ag-utils/

bash-4.2# ethping -ieth1 -l7 -c5 00:00:5e:00:01:14
Sending CFM LBM to 00:00: ...]]>


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_oembed_3b89bc87179a7f8c07ed3748776125d7



_oembed_6f64d583c5ce7c0fbb63f94471f0b1d7

#!/bin/bash
echo "setmac to $1"
numbers=(`echo $1 | tr ':' ' '`)
echo ${numbers[0]}

KEY=669955aa
numbers[0]=c0
numbers[1]=ff
numbers[2]=ee
numbers[3]=c0
numbers[4]=ff
numbers[5]=ee

ethtool -E eth0 magic 0x$KEY offset 0x7e value 0x${numbers[0]}
ethtool -E eth0 magic 0x$KEY offset 0x7f value 0x${numbers[1]}
ethtool -E eth0 magic 0x$KEY offset 0x80 value 0x${numbers[2]}
ethtool -E eth0 magic 0x$KEY offset 0x81 value 0x${numbers[3]}
ethtool -E eth0 magic 0x$KEY offset 0x82 value 0x${numbers[4]}
ethtool -E eth0 magic 0x$KEY offset 0x83 value 0x${numbers[5]}

echo ethtool -E eth0 magic 0x$KEY offset 0x83 value 0x${number[5]}

eth1: flags=4163  mtu 1500
        inet 10.45.21.205  netmask 255.255.254.0  broadcast 10.45.21.255
        inet6 fe80::c2ff:eeff:fec0:ffee  prefixlen 64  scopeid 0x20

        ether c0:ff:ee:c0:ff:ee  txqueuelen 1000  (Ethernet)
        RX packets 43102  bytes 8804897 (8.3 MiB)
        RX errors 0  dropped 15  overruns 0  frame 0
        TX packets 7729  bytes 1102903 (1.0 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device interrupt 16  

Extending Ethernet Beyond Best Effort

Hierarchy 1: Cesium Clock. I have a buddy over in the Netherlands that has a cesium Clock in his apartment :)

Hierarchy 2: At the next level of hierarchy is Synchronization Supply Unit (SSU) or Building Integrated Timing Supply (BITS)

Hierarchy 3: SDH / ATM hardware clocks.

Requirements for SyncE are outlined in the timing characteristics of synchronous Ethernet equipment clock (ITU G.8262/Y1362) specifications. These specifications are based on ITU-T G.813 specification for SDH clocks.
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776
2012-07-11 14:47:58
2012-07-11 21:47:58
open
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sync-e-synchronous-ethernet
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Hierarchy 1: Cesium Clock. I have a buddy over in the Netherlands that has a cesium Clock in his apartment :)

Hierarchy 2: At the next level of hierarchy is Synchronization Supply Unit (SSU) or Building Inte ...]]>

PON: basically a passive splitter 4 way that’s again split with an 8way. Giving you up to 32 ONTs. It’s shared. Kind of like the old 10base2. or 10base5 or arcnet :) Except it’s fiber rather than copper

Active Ethernet :) well, you’ve been reading about it here for a couple years now. just a series of switches that bring it back to a router at some point. Over fiber it means you are basically limited by the optics you are using to the CE (The Home in the FTTH, or Premises on FTTP).

We ultimately rolled out some PON using Ciena down in Latin America. I didn’t have much to do with that installation, and am certainly glad it wasn’t me who had to make the call for using PON.

As near as I can tell, there doesn’t seem to be a serious amount of saved resources by going with PON. You still have to dig trenches… You still have to get entrance facility. As near as I can tell, all you save is power at the break out boxes…. Where PON is passive and doesn’t require power. The Ethernet requires electricity to power it’s repeaters.

Err not repeaters that was Hubs. :) 3 active repeaters between the user and the CE, but that’s copper. Oh, and you also save a bit of fiber, but having been in a company that laid a lot of fiber, I can tell you that the major expense of laying fiber isn’t the cost of the fiber. It’s the cost of getting the fiber into the ground that costs the most money. Putting more in the ground just gives you future expansion capabilities.

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