|How can propagation time be greater than transmission time?|
Transmission time = time it takes to send
(dispatch) the data.
Propagation delay = time it takes for the data to
reach the other side.
For example, suppose you're sending 10 bits of
data from the North Pole to the South Pole. If,
for example, your computer (which is very old) has
a 1bit/ms bit rate for sending, the transmission
time would be 10ms. However, due to the length and
|Two computer on a same IP?|
Use unique ports for the clients and servers
running on the same machine. In addition 127.0.0.1
is localhost (internal to that machine). Computer
B cannot communicate with 127.0.0.1 on Computer A.
Use 127.0.0.1 if all applications or on the same
machine. Use the computers actual IP address if
you want external machines to be able to
communicate with the server.
|adaptive jitter buffer without packet loss|
When jitter clears up, you merge packets and
'accelerate' the buffer.
Merge offcourse will need appropriate handling,
but the idea is to pop 2 20ms packets from ajb and
creating a 30ms packet. you keep doing this until
your buffer levels are normal.
Similarly for underrun, packets can be 'stretched'
in addition to introduction of latency.
|dual public IPs for same adsl connection?|
I figured out the issue by myself. IT cant have 2
public ip for the same device(router in my case}
at the same time. The thing was the servise
provider has issued me some generated ip and it is
not a public ip. I was behind a NAT. So when i
called them, they allowed my roter to get a real
public ip and that solved the issue.
|openMPI/mpich2 doesn't run on multiple nodes|
Usually this is caused because you didn't set up a
hostfile or pass the list of hosts on the command
For MPICH, you do this by passing the flag -host
on the command line, followed by a list of hosts
mpiexec -host host1,host2,host3 -n 3
You can also put these in a file:
Then you pass that file on the command line like
|Raspberry Pi - run a program with specified internet connection|
Well, it seems that I should use network
namespaces. Here are the links, that may be
helpfull to visitors of this question. I didn't
find another ways how to do it.
|Can someone tell me the benefits of using a public subnet?|
I work for an ISP and we allocate public subnets
to client that require port forwarding within
their local network.
In my case, we own the routers on site and
customers do not have access to them, this means
any time they would like to do a port forwarding
they would need to call in a place a ticket.
However if you have your own public subnet, then
you can connect your own router to this and do
|Restarting CoreOS missing files|
Files on disk shouldn't disappear on you like
that. Did you happen to PXE-boot this VM or
somehow use a file system in RAM?
A better way to do this config is with
cloud-config, which CoreOS uses to configure
machines at boot. It's intended to provide a
repeatable way to set up networking, mount disks
and things like that. The steps that you completed
manually can be done with cloud-config like th
|What is the difference between a physical address and MAC address in networking?|
Physical address and MAC address are indeed the
They are used to communicate between devices on
When you send a request to a remote host's IP
address (access a website for instance) your
computer sends that request to your LAN's gateway
(your router) and it uses its physical (MAC)
address as the destination of the message but the
logical (IP) address of the host for its fi
|Run a hadoop cluster on docker containers|
I did this with two containers running master and
slave nodes on two different ubuntu hosts. I did
the networking between containers using weave. I
have added the images of the containers on docker
hub account div4. I installed hadoop in the same
way, as its installed on different hosts. I have
added the two images with coomands to run haddop
on them here: