Connecting Mobile Workstations to the Internet Over a Digital Cellular
Markku Kojo, Kimmo Raatikainen, Timo Alanko, Univ. of Helsinki
One-line abstract: Indirect TCP type approach in which MH apps can
use either traditional TCP or Mowgli sockets (socket/transport/dgram/network
layer that replaces TCP/IP but provides similar API). Both connection types
go through a wired proxy. Disconnection handled in transport layer.
- TCP/M-IP compatible indirect-TCP implementation using "Mowgli sockets"
API. Mowgli Socket Interface Protocol is like ICMP for wireless link; Mowgli
Wireless Link Proto does stuff like header compression, etc.
- Mowgli Virtual Socket Layer demuxes stuff to either Berkeley sockets
or Mowgli Wireless Msg Protocol/Mowgli Socket/MWLP stack. (See fig. 5 in
- "Mobile-aware" apps can use additional mobility support in
M-sockets, e.g. "QoS interface" (proposed but not defined).
- Claim: proxy is not a bottleneck; slow wireless link is (by defn).
- Future work: distinguishing different qualitative types of communication
service needed by apps, and develping QoS models; specification of services
needed for mobility awareness; security (no elaboration given).
- Great architecture for dealing w/disconnection, if you're willing to
do that at the transport layer - an open argument.
- The Mowgli Socket Protocol they talk about seems to have evolved into
the MWLP/MDCP described in the Mowgli-WWW paper
- QoS discussion lacking - no direct specification of the QoS params (but
then, neither do we...)
- Indirect TCP was done before and has been shown to not necessarily be
a good thing; main point here seems to be to provide Mowgli sockets as the
"preferred" MH interface, but to allow for a compatible interface
- Not clear if the transport layer is the place to deal w/disconnection;
isn't that more an end-to-end problem that applications should solve? (Though
GloMop deals with part of it in session layer, it notifies apps of disconnection,
and can serve a disconnection request from an app.)
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