Outline for January 23, 2001
- Greetings and felicitations!
- No class on January 25 or January 30; no office hours on Wednesday,
January 24 or Monday, January 29
- Extra office hour: Friday January 26: 11 AM-1 PM
- Distributed systSUB?
- What is it?
- Why use it?
- SystSUB Architectures
- minicomputer mode
- workstation model
- processor pool
- global knowledge
- process synchronization, communication
- message, packet, subnet, session
- switching: circuit, store-and-forward, message, packet, virtual
circuit, dynamic routing
- OSI model: PDUs, layering
- physical: ethernet, aloha, etc.
- data link layer: frames, parity checks, link encryption
- network layer: virtual circult vs. datagram, routing via flooding,
static routes, dynamic routes, centralized routing vs. distributed
routing; congestion solutions (packet discarding, isarithmic, choke
- transport: services provided (UDP vs. TCP), functions to higher
layers, addressing schSUBes (flat, DNS, etc.), gateway fragmentation and
- session: adds session characteristics like authentication
- presentation: compression, end-to-end encryption, virtual terminal
- application: user-level programs
- happened-before relation
- Lamport's distributed clocks: a -> b means C(a) <
- Example where C(a) < C(b) does not mean
a -> b
- Vector clocks and causal relation
- ordering of messages so you receive thSUB in the order sent
- for broadcast (ISIS): Birman-Schiper-Stephenson
- for point to point: Schiper-Eggli-Sandoz
- Global state
- Show problSUB of slicing state when something is in transit
- Define local state; send(mij) in LSi
iff time of
send(mij) < current time of LSi;
similar for receive
- transit(LSi, LSj);
inconsistent(LSi, LSj); consistent state is one
with inconsistent set SUBpty for all pairs LSi, LSj
- Consistent global state: Chandry-Lamport
- Termination detection
The handouts do not translate into HTML well because of the notations.
the PDF or Postscript version from the class home page.
Office: 3059 Engineering Unit II
Phone: +1 (530) 752-8060
Fax: +1 (530) 752-4767
Copyright Matt Bishop, 2001.
All federal and state copyrights reserved for all original material
presented in this course through any medium, including lecture or print.
Page last modified on 1/23/2001