Monday, August 3, 2020

VPLS.US 10/24/2012 10.10.5.1 & 10.10.5.2

I was just asked the most interesting question.


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.

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 benzinga.com 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, benzinga.com 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.

VPLS.US 09/30/2012 802.1ag for unix

http://vpls.us/?p=780 Sun, 30 Sep 2012 18:07:58 +0000 timc
http://vpls.us/?p=780

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 00:00:5e: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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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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http://vpls.us/?p=786 Tue, 02 Oct 2012 18:16:20 +0000 timc
http://vpls.us/?p=786

#!/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]}

Had some problems finding the the magic, but after that it was all downhill

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  

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786
2012-10-02 11:16:20
2012-10-02 18:16:20
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macs
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#!/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 ...]]>


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http://vpls.us/?p=792 Thu, 04 Oct 2012 18:17:52 +0000 timc
http://vpls.us/?p=792


RFC 2544 Applicability Statement: Use on Production Networks Considered Harmful

2544 is to be considered Harmful :) oh wow, so we've been using testing procedures that are to be considered harmful. Yeah, we knew all that :P We just haven't had many other options. The new Y.1564 standard that is out from the ITU-T is going to go a long way towards rectifying a lot of the problems of testing Ethernet in the last mile between the PE and CE. However, what is really a Gem is hidden in the back of that little document. Back in Appendix I. CBS and EBS test methodology. It describes the tests that are included to be preliminary or experimental, and for informational purposes only. I'm not sure why that is, perhaps the tests really aren't applicable to a real world test and probably more geared towards the testing of lab gear? I guess that would be my initial guess as to why they weren't included in the formal document. However for the lab. OH YEAH. This is cool. E.3 basically lets the tester, run tests against the hardware buffers to determine the buffer capacity.

Let me repeat that. E.3 allows a tester to test the buffer capacity of a circuit / interface / hardware / switch, etcetra.... Line item 4 on E.3 says to test EBS.

the transmitter turns off for the smallest amount of time necessary
to ensure that the B-e token bucket is full and has overflowed by an amount
equal to or greater than 2%(EBS). Then the transmitter bursts the largest
number of back-to back (minimum interframe gap) frames that will drawn down
the Be token bucket until the number of tokens is more than or equal to

Being the geek that I am, I was drooling when I read that. I've been burned by so many switch vendors that don't allocate enough buffer space to their small interfaces on a switch and the first time you try to send traffic from the core to the edge interface in that box, it' pukes, or more specifically just starts puking packets out of it's buffers, making customers call in and complain. The customers calling in and complaining is by far the worse.

The only draw back is that I have to ask the vendors if they support ITU-T 1564 SAM Appendix I
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VPLS.US 06/11/2011 Sync-E Synchronous Ethernet

http://vpls.us/?p=776 Wed, 11 Jul 2012 21:47:58 +0000 timc
http://vpls.us/?p=776

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
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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 ...]]>

VPLS.US 06/26/2011 Active Ethernet Versus PON

http://vpls.us/?p=764 Sun, 26 Jun 2011 17:29:08 +0000 timc
http://vpls.us/?p=764

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



PON Passive Optical Splitter

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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VPLS.US 06/25/2011 using vpls for e-line

http://vpls.us/?p=756 Sat, 25 Jun 2011 01:48:59 +0000 timc
http://vpls.us/?p=756

using vpls for e-line

This is a pretty interesting question.

On the one hand you could use RFC 4447, using LDP to setup Pseudowire connections between two PEs. That’s pretty simple, straight forward, and with minimal amount of resources that get carved up by the PEs terminating the VC Virtual Connection.

Or, on the other hand, you could use 4762 to establish the point to points between the two CEs. Well there are trade offs for the least use of resources.

With RFC 4447:

  • You have to do some sort of migration if they want to go from ELINE to ELAN.
  • You don’t have any sort of MAC learning.
  • All BPDUs are automatically carried across the link.
  • It has the traditional carrier feel of a circuit being tied up.
  • No routing table is configured on the resources.
  • The turnup / build of a 4447 is MUCH simpler, in most cases the configuration is a single line of code.
  • The training / testing / operational aspects are MUCH simpler.

With RFC 4762:

  • No configuration Migration between ELine to ELan
  • Typically most Router Vendors will allow much deeper packet inspection of L2VPN instead of a Pseudowire. For instance I know of one larger router vendor that will allow classification via DSCP/TOS/Prec using 4762 but not with 4447
  • MAC learning can be turned off to make the behavior similar
  • Configuration is MUCH more complex
  • Traversing a Bridge-domain allows an additional touch point for troubleshooting exercises with the customer.
  • Adding additional sites is easy
  • Passing L2 protocols can require additional Configuration

There are trade offs for every scenario. I guess my main concern with using 4762 for building point to point ethernet is the situation where you are building EVPL or a Etree using point to points. Your trunk will have potentially hundreds of end points and building all of those VPLS 4762 tables seems to be a very large chore.

Then the other thing that has to be considered is the impact of the decision as it relates to your metro area. Turning off MAC learning at your PE doesn’t do anything to limit the amount of addresses that you could or will be seeing in your metro rings. Assuming of course that you don’t extend your pseudowires into the metro. That makes the decision of using VPLS in the metro even much more complex.

Personally, I’ve waffled between the different design theories, and have been swayed because of the features and capabilities of the vendors. However the end result to the customer is identical.

What is everybody else doing?
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