# what I can expect in bandwidth for a 100MB point to point

I'm trying to get my figures right. I put in a point to point 100MB circuit.

From my site (west coast) to my DR (east coast) is roughly 58ms latency. Confirmed via tracert and ping from laptop though p2p to another laptop sitting on the other side.

This is my 1st p2p in a company so I'm not sure what to expect.

So doing some searching on google I came across a few calculators. I'm seeing about 5.5 -9 Mb throughput on.

I used this site link as well as link this site to get a quick idea.

Is my thinking correct on this? is this what I can expect? Can I do something like those links say by increasing the tcp window size to get a full 100MB out of the line? This link is for replication of terabytes and 5.5-9Mb will take forever..

I've done a few tests with sftp back and forth and the line is dog slow which brings me here.

attached is a few pics and my config all in a pdf.
Drawing1.pdf
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Commented:
You're mixing up your big and small Bs.  1 B (Byte) = 8 b (bit).
So to go from bits to bytes, you should divide by 8, although 8 is a theoretical number that doesn't take into account network overheads.  Best to keep it simple and divide by 10, which is more realistic anyway.

So what line did you purchase?  If you purchased a 100 Mbps or Mb/s (small b), this would be equivalent to 10 MB/s (big B).  if you're seeing up to 9 MB/s, then this is about right.
Author Commented:
yup, sorry my mistake on that one, you are right...

I purchases a 100MB (big M big B) circuit.
So you got a circuit that is 100MBytes/sec or roughly 1Gbit/sec of throughput. So this is 10 times faster that most local LAN's. Is this correct the way I put it?

Author Commented:
100MB big M big B..

here is a snip from the contract...

Product        Qty   term
Ethernet Pt-Pt 1 3 YR

Ethernet 100 MB Full Rate 1 3 YR

so yes.

but look at the attachment.. its dog slow...
I have not seen a commercial 1Gbit/sec line. I think that would be dedicated fibre coast to coast.

I looked at your picture and it is slower than my 10MBytes (100Mbits) local house LAN. Even so, it takes (at full available local speed) about an hour to copy 100Gbytes of machines from one PC to the other PC.

You probably need to get the vendor to help you with throughput capability.

Author Commented:
I have not seen a commercial 1Gbit/sec line. I think that would be dedicated fibre coast to coast

as in personally our as in they don't exist?
Author Commented:
I have been talking to my isp.. but they are hell. I always get the its your equipment line.

I wonder how that can be because I only have a laptop connected at either side...
I am not saying they cannot exist, just that I have never seen one. Commercial offerings for high speed lines normally top out at 100Mbits/sec.

So all I am saying is that your vendor is the next call for you to make.

You would have to a special routers at each location and fibre optic cable to the router. An ordinary Netgear router is not likely to connect up to a leased line at 1Gbit/sec.

You are talking about leased line speeds as much as 100 times faster than most of us have.

Something is wrong with this picture at this point. ... Thinkpads_User
Author Commented:
The netgear and Cisco are my stuff, the telco dropped it fiber to my facilities and handed off a 100Mbyte Ethernet to me.

The vendor refers to this as " oc3" I believe.
Commented:
I've not used point-to-point, so I'm not sure what sounds normal either.  I've just googled a few plans and they all seem to use Mb or Gb (small b).  It's so weird that yours doesn't mention "per second" on your contract.  100 MB isn't a speed.  Your plan says "Ethernet Pt-Pt 1" and I'm not sure what that 1 means.  A T1 line would be 1.5 Mbps.  I think you wanna be absolutely sure what you've paid for before you go stressing and troubleshooting.  Can you find the plan on the company's website, or show us?
Author Commented:
The 1 is quantity
Commented:
Oh yeah ;>
Ahh well OC3 is:
http://www.infobahn.com/research-information.htm
OC-3 - 155 megabits per second (100 T-1s) Ave. cost \$20,000.-\$45,000./mo.
Does that sound the correct cost?
Author Commented:
Yup
theras2000 - I had not thought about volume of data for the plan because the original question was about speed but you are probably right.

jdizz - I appreciate the difficulty with your ISP, but you do need to clarify with them.

Author Commented:
Thanks guys I believe you're all right but I'll leave this open for a bit ( not byte) to see if anyone else weights in. If not I'll award u guys the points.
Commented:
Haha nice one.
Commented:
No points :)
All your questions should be directed to your ISP. If they say "its your equipment line" - ask them to demonstrate real speed with their equipment. 78 ms delay (when you've measured it? During file transfer or when channel was free?) seems too big. This delay should be in SLA.
Commented:
You can't compare Asynchronous Transfer Mode (ATM) cloud technology to Broadband. The claims on throughput for an ATM connection stems from a Basic Rate Interface (BRI) This is a single channel that is equivalent to an ISDN. Yes, an ISDN is also ATM technology and is the basic unit for one channel. It connects within a central office using a Digital Subscriber Local Access Multiplexer (DSLAM). A DSLAM will combine T1's, fractional T1's, and ISDNS into a group of channels. This is where an OSC-3 comes in handy. An OSC-3 is a part of the ATM cloud technology usually found in a phone company central office to communicate with other central offices over ATM. An OSC-3 is equivalent to 10 T1's, or 240 channels of BRI-128K.

Broadband, is channelized, but not in the way you might think. On a broadband cable or broadband cellular connection, you are sharing the channels using a different type of multiplexing where you share the entire bandwidth with whomever is on the line. So, at certain times, you may see slowness, and other times it may appear as great throughput. Broadband is very much like the old Ethernet days where everyone taps into the same line for multiple access. There is a means to delegate a certain amount of bandwidth for an individual user on the broadband connection.  This is used when you have a defined service agreement with your broadband carrier. Unlike ATM, This switching and routing is done virtually. ATM is strictly hardware channeling using multiplexing technology.

In your case, the point to point tunneling will have packets that carry the typical overhead of any other TCP or UDP packet. The difference is, on a tunneling packet, you will have additional overhead to route through the tunnel (hopefully an encrypted tunnel to prevent from man in the middle attacks). Encryption and routing through a tunnel virtually will always increase packet headers and your percieved throughput will be much slower. If you prevent your packets from reducing the payload of the packet, or don't participate in Jumbo Frames through the ISP, you will have a networking fault called Maximum Segment Size Exceeded. The protocol used to determine what the payload can be for a proper sized packet is called ICMP (also used for Ping).

WATCH OUT: What happens during Packet Maximum Transferable Unit Discovery (PMTUD) is your local computer will send out an ICMP to the distant station basically figuring out he payload size you can have for the packet to navigate across the connection, through the tunnel, on to the other side. If this packet size is exceeded, the packet will be dropped and TCP will request the packet again or your connection may time out with only partial data collected for the entire session. So, what you will see are things like partial web pages, partial updates and hosed up operating systems, mail problems, timed out web pages, etc...

Since you are asking this question, I assume the tunneling doesn't appear as it should. You will get about 50% payload for a connection, the rest is routing. If your connections are having many problems, it's probably because you are exceeding the payload permitted through the routed tunnel.

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