I need to understand the amount of data transmitted by Pingplotter. If I'm doing a continuous ping with a trace interval of 15 seconds, just how much actual data is traveling across my network? Or how many (of what size) packets?

Assuming that a given site shows 5 total "hops", just how much data am I moving every 15 seconds?

Hi, John. Some of this is dependant on your network environment, but in general each packet takes up the bandwidth listed by "Packet size", plus the ethernet overhead (14 bytes for 2 mac addresses and a packet type identifier). So, if you have your packet size set to 50 bytes, the actual *outgoing* packet is going to be 64 bytes (which includes the ethernet framing addition).

Returning packets are normally 70 bytes for intermediate hops or some routers will return the cargo too - which will add some additional size. The final destination will ping back with all of the cargo normally, which puts that returning packet size at the same as the outgoing ping request.

So, for a 5 hop target, if you use the default 50 byte packet, your outgoing bytes are going to be 320 bytes (5 times 64 bytes) and the returning bandwidth is going to be 344 bytes (4 times 70 for the intermediate hops, plus 70 bytes for the final destination response).

We space each outgoing packet a bit so this doesn't all go out at once. With the default 25 ms spacing between packets, this puts the "rate" of data at 2.56 KBps with the parameters above, but only for a short burst each second. Returning packets will be a bit lower rate, usually, because consecutive hops usually take longer to respond.

Since you're probably using the default packet size of 56 bytes, with 5 hops every 15 seconds, you're moving 350 bytes upstream and 350 bytes downstream every 15 seconds (we pick 56 bytes packet by default because this makes the intermediate responses the same size as the final destination, in most cases).

Note that the data stream most network monitors use does not include the ethernet header, so if you're measuring this with some tool, you might see 280 bytes instead of 350 in both directions.

- Pete

i connect to verizon dsl using windows xp pro with pppoe (network connections software). my westell dsl modem doesnt have any pppoe firmware. pppoe further encapsulates the ethernet frame. windows xp pppoe ip mtu is 1480. The 20 bytes of overhead consist of the PPPoE header (6 bytes), the largest possible outer PPP header (4 bytes), the largest possible Multilink PPP header (4 bytes), the largest possible PPP header for compression and encryption (4 bytes), and the PPP header that identifies the actual packet being sent (2 bytes).
do i also have to add an addtional 20 bytes for pppoe when calculating an icmp packet?
56(default)+14(ethernet)+20(pppoe)= 90 bytes outgoing

That's the way I'd calculate it - at 90 bytes of raw traffic.

ok, thanks.