* Slow/expensive link for high-volume data, bad QoS: UsecaseQoS.
* Extreme terrestrial environments, no link: UsecaseNoLink.
* One-way broadcasting communications: UsecaseBroadcast.
+* Satellite links: UsecaseSatelliteLinks.
* Private, isolated MitM/Sybil-resistant networks: UsecaseF2F.
* Highly secure isolated air-gap computers: UsecaseAirgap.
* Network censorship bypassing, health: UsecaseCensor.
* Reconnaissance, spying, intelligence, covert agents: UsecaseSpy.
+* Cheap night transfers: UsecaseCaller.
@end menu
@node UsecaseMail
The command:
@verbatim
-% nncp-file file_i_want_to_send bob:
-% nncp-file another_file bob:movie.avi
+$ nncp-file file_i_want_to_send bob:
+$ nncp-file another_file bob:movie.avi
@end verbatim
will queue two files for sending to @emph{bob} node. Fire and forget!
later than the other ones. Nearly all commands has corresponding option:
@verbatim
-% nncp-file -nice 32 myfile node:dst
-% nncp-xfer -nice 192 /mnt/shared
-% nncp-call -nice 224 bob
+$ nncp-file -nice FLASH myfile node:dst
+$ nncp-xfer -nice PRIORITY /mnt/shared
+$ nncp-call -nice NORMAL bob
[...]
@end verbatim
You can also use CD-ROM and tape drives:
@verbatim
-% nncp-bundle -tx bob | cdrecord -tao -
-% nncp-bundle -tx bob | dd of=/dev/sa0 bs=10240
+$ nncp-bundle -tx bob | cdrecord -tao -
+$ nncp-bundle -tx bob | dd of=/dev/sa0 bs=10240
@end verbatim
@node UsecaseNoLink
device (SD is preferable!), mount it and run @ref{nncp-xfer}:
@verbatim
-% nncp-xfer -node bob /media/usbstick
+$ nncp-xfer -node bob /media/usbstick
@end verbatim
to copy all outbound packets related to @emph{bob}. Use @option{-mkdir}
outgoing packets.
@verbatim
-% nncp-xfer /media/usbstick
+$ nncp-xfer /media/usbstick
@end verbatim
Unmount it and transfer storage to Bob and Alice. When they will insert
it in their computers, they will use exactly the same command:
@verbatim
-% nncp-xfer /media/usbstick
+$ nncp-xfer /media/usbstick
@end verbatim
to find all packets related to their node and copy them locally for
a sequence of @ref{Encrypted, encrypted packets} you can catch on.
@verbatim
-% nncp-bundle -tx alice bob eve ... | command to send broadcast
-% command to receive broadcast | nncp-bundle -rx
+$ nncp-bundle -tx alice bob eve ... | command to send broadcast
+$ command to receive broadcast | nncp-bundle -rx
@end verbatim
With built-in packet duplicates detection ability, you can retransmit
your broadcasts from time to time, to increase chances the recipient
will catch them by regular stream listening.
+@node UsecaseSatelliteLinks
+@section Satellite links
+
+Satellite links have @strong{very} high delays together with high
+bandwidths. You can send several megabits of data per second, but they
+will reach the remote side only after half a second!
+Most file sharing protocols like
+@url{https://en.wikipedia.org/wiki/Files_transferred_over_shell_protocol, FISH},
+@url{https://en.wikipedia.org/wiki/FTP, FTP},
+@url{https://en.wikipedia.org/wiki/Secure_copy, scp},
+@url{https://en.wikipedia.org/wiki/XMODEM, XMODEM}
+will perform very badly because of round-trips quantity. Each file
+transmission explicitly generates request and acknowledgement packets
+that are send over the link. Remote side won't do anything until it
+receives them. Moreover not all protocols allow duplex data
+transmission (when both sides are sending data simultaneously).
+
+NNCP's @ref{Sync, synchronization protocol} (SP) tries to mitigate all
+that issues by reducing number of round-trips, number of packets passing
+through. All file lists, file download requests are grouped together
+(pipelined) in one huge packet. Only transmission halt and successful
+file download acknowledgements are sent explicitly. SP could be asked
+only either to upload or download packets for our node. SP could ignore
+files with low priority. Full files listing is passing even during the
+handshake procedure.
+
@node UsecaseF2F
@section Private, isolated MitM/Sybil-resistant networks
property.
@verbatim
-% nncp-daemon -bind [::]:5400
+$ nncp-daemon -bind [::]:5400
@end verbatim
will start TCP daemon listening on all interfaces for incoming
connections.
@verbatim
-% nncp-call bob
+$ nncp-call bob
@end verbatim
will try to connect to @emph{bob}'s node known TCP addresses (taken from
configuration file) and send all related outbound packets and retrieve
NNCP supports packets relying (transitioning) out-of-box.
@verbatim
-neigh:
- bob:
+neigh: {
+ bob: {
[...]
- addrs:
- lan: [fe80::5400%igb0]:5400
+ addrs: {
+ lan: "[fe80::5400%igb0]:5400"
+ }
+ }
bob-airgap:
[...]
- via: [bob]
+ via: ["bob"]
+ }
+}
@end verbatim
That @ref{Configuration, configuration file} tells that we have got two
transferred files and mail messages) could and should be done on a
separate computer (@ref{nncp-cfgmin} command could help creating
configuration file without private keys for that purpose).
+
+If you really want to carry your private keys, then @ref{nncp-cfgenc}
+command will be able to encrypt your configuration file. Passphrase you
+enter is strengthened with both CPU and memory hard function.
+
+@node UsecaseCaller
+@section Cheap night transfers
+
+Your Internet/telephone traffic price can vary, depending on daytime.
+Night calls/connections could be twice as cheaper. You wish to send your
+files at that time, but keep high priority email infrequently passing
+through in anytime. Also you wish to pass any kind of traffic when the
+node is available through the LAN.
+
+You can easily set your preferences in @ref{Call, call
+configurations} for @ref{nncp-caller} command used in online
+communications.
+
+@verbatim
+neigh: {
+ [...]
+ some-node: {
+ [...]
+ addrs: {
+ lan: "[fe80::be5f:f4ff:fedd:2752%igb0]:5400"
+ wan: "some-node.com:5400"
+ }
+ calls: [
+ {
+ cron: "*/1 * * * *"
+ addr: lan
+ nice: MAX
+ onlinedeadline: 3600
+ },
+ {
+ cron: "*/10 * * * *"
+ addr: wan
+ nice: PRIORITY
+ xx: rx
+ },
+ {
+ cron: "*/1 0-7 * * *"
+ addr: wan
+ nice: BULK
+ onlinedeadline: 3600
+ maxonlinetime: 3600
+ },
+ ]
+ }
+}
+@end verbatim