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V.T. Eric Layton

Fun With Networking

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amenditman

Hmm... I haven't had any issues with my Westell 9100EM (Verizon provided) multi-purpose device. It's not just a router, you know... it's a switch/router/access point/DHCP server-client/firewall/NAT-PAT IP translator. :)

 

I can say carp like the above with authority now that I'm Cisco certified. :lol:

Show off Mr. Smarty Pants, you've earned it.

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V.T. Eric Layton

That's me... Mr. Party Smants. ;)

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ross549

NAT-PAT, eh?

 

Adam

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mac

Hmm... I haven't had any issues with my Westell 9100EM (Verizon provided) multi-purpose device. It's not just a router, you know... it's a switch/router/access point/DHCP server-client/firewall/NAT-PAT IP translator. :)

 

I can say carp like the above with authority now that I'm Cisco certified. :lol:

 

The Pace/2Wire 3801HGV residential gateway provided by AT&T for my Uverse bundle does all of that plus IPTV and takes my VOIP service and sends it out over my CAT3 phone wire to all the RG11 outlets in the house. However the AP is G, so if you want N speeds, you'd have to add your own AP. Since I'm close to the VRAD that converts the fiber line to copper wire (about 600' away) I can get up to 24/3 HSI and 4 simultaneous HDTV channels and the main TV receiver (every TV must have a receiver) has a built-in 500GB HDD for a DVR. It's amazing to me that all of this is transmitted over 40+ year old buried 2 pair copper wire to my house. It's not cheap though, about $170 a month after the 12 month sign-up discounts are over.

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V.T. Eric Layton

Amazing what you can do with copper, eh?

 

I'm still in the last century when it comes to television viewing. Not only do I watch programs from the 40s, 50s, and 60s, but I also get all my television data the old fashioned way... over the airwaves! :)

 

TV-antennas.jpg

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ross549

We have Winegard SquareShooter 2000 in our attic, and it picks up the local channels just fine. We don't pay for cable tv, and we really don't watch the local stuff either. We did watch a couple episodes of the old Batman (Adam West) a week ago. We just don't have time for TV. I don't know how folks have so much time to watch it.

 

Adam

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V.T. Eric Layton

I don't really watch a lot of TV. I watch The Rifleman pretty regularly, and maybe Perry Mason a couple times a week, and the occasional PBS show... Nova, Masterpiece Theater, etc. That's about it for me, though. I can't remember when I last watched a prime time network show of any sort.

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Temmu

not sure if anyone cares about the router flap q any more, but yes, it does matter to home users because they may loose a connection to some site or other. it's improbable that a home user can do anything about it because what major carrier is going to listen to them? and flap is just that, when a router keeps choosing another route every few seconds. you can observe it by radically different ping times, or loss of connection, typically seen in downloads.

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V.T. Eric Layton

Actually, I was waiting for the explanation. Thanks. :)

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V.T. Eric Layton

Ian asked me a couple questions via PM about the OSI Model and the TCP/IP Stack and how they work. I'm going to copy my answers to him here because they are good info for everyone who may be interested. :)

 

=====

 

OSI lost out to the TCP/IP model many, many years ago. However, the different OSI layers are still used and referred to often in the industry. The Cisco cert exam focuses mostly on what goes on on the first 4 layers (1-4) of the old OSI model. It's more important that you know which devices work on which layers for Cisco. For example - hubs and repeaters work on Layer 1, bridges and switches on Layer 2, Routers on Layer 3, TCP and UDP protocols on Layer 4, etc.

 

Unlike CompTIA certs, Cisco is more about the actual interconnecting devices used to get data across a network. Speaking of the CompTIA certs, I'm planning on taking the Network+ and A+ very soon after taking my second Cisco exam (ICND2-CCNA). Fun! :)

 

OSI

 

7- Application

6- Presentation

5- Session

4- Transport

3- Network

2- Data-link

1- Physical

 

TCP/IP

 

4- Application

3- Transport

2- Internet

1- Network Interface

 

There's a pretty good explanation of the OSI model at wikipedia --> https://en.wikipedia.../wiki/OSI_model

 

=====

 

TCP (Transfer Control Protocol) and UDP (User Datagram Protocol) work at Layer 4 (OSI - Transport). This is where segmentation, flow-control, error correction, etc. all take place. Protocol Data Unit (PDU) = a segment

 

Routers live on Layer 3 (OSI - Network). Their sole purpose in life is to route packets between different subnets. Protocol Data Unit (PDU) = packet.

 

Bridges and Switches (collections of bridges in one box) work at Layer 2 (OSI - Data-link), where they use MAC addressing to forward frames to appropriate destinations. Protocol Data Unit (PDU) = a frame.

 

Hubs and repeaters work on Layer 1 (OSI - Physical). They are stupid devices (that you're rarely see these days) that just flood any incoming signals out all their outgoing interfaces. Protocol Data Unit (PDU) = bits

 

Weeeeeeee! :)

 

=====

 

To fully understand the OSI or TCP stack, you need to understand encapsulation. Bits at the Physical layer are encapsulated into frames at the Data-link layer, then those frames are encapsulated into packets at the Network layer, and finally at the Transport layer the packets are encapsulated into segments. At each stage, the encapsulation adds to the information being passed up the stack. When two devices across the world (or room) communicate with one another, the data runs the stack, down the stack, and back up the stack in its journey from source to destination.

 

Clear as mud, eh? :)

 

http://learn-network...the-tcpip-model

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goretsky

Hello,

 

My very general rule-of-thumb from several years ago, was that if you were working at Layer 7, than you were dealing with software, e.g., WinSock. If you were were working at Layers 2-3, you were doing hardware (switches). These days, I spend far more time at layer seven and up, but it's nice to take a vacation and visit lower layers of the stack sometimes for a little... bit.

 

Regards,

 

Aryeh Goretsky

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V.T. Eric Layton

Yeah, you have to stick your head under the hood and get a little greasy every once in a while, Aryeh. It's good for you! :)

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amenditman

That's me... Mr. Party Smants. ;)

At least they're not Smarmy Pants!
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V.T. Eric Layton

Good point.

 

+0.250

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Temmu

you bring up a good point, eric.

+1

oops! wrong thread!

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securitybreach

I do not know how I missed this thread. Great stuff!!! :thumbup:

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V.T. Eric Layton

I do not know how I missed this thread.

 

You have to come outside of BATL every once in a while to associate with the rest of the unwashed masses. It's OK, though. We can go back and lock ourselves in BATL when we've had enough. ;)

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securitybreach

You have to come outside of BATL every once in a while to associate with the rest of the unwashed masses. It's OK, though. We can go back and lock ourselves in BATL when we've had enough. ;)

 

Right....... B) :P

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Temmu

lol, well, i resemble that...

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