Class04

as slideshow

Protocols

Part 3 2/4/2009

Questions?

any questions?
speed of light

Applications: Network Management

network management software

Theory

SMI
- structure of management information
- rulebook and toolkit
MIB
- management information base
- layout and questionnaire
SNMP
- simple network management protocol
- managers and agents
  - agents can send data to manager
  - manager can request data

unsolicited data from agent to manager is snmptrap

(regular) snmp is when manager requests data

RMON

remote monitoring
- Statistics
- History
- Alarms
- Events
- Host
- HostTopN
- Matrix
- Filters
- Packet Capture
statistics and functions in Ethernet MIB

ISO Model

FCAPS
- Fault Management
- Configuration
- Accounting / Administration
- Performance
- Security

UNC Network Management

user information tool with statistics
the following slides as pdf, and all those with a few more in another pdf

UNC Network Management: F1

UNC Network Management: F2

UNC Network Management: C1

UNC Network Management: A1

UNC Network Management: A2

UNC Network Management: P1

UNC Network Management: P2

UNC Network Management: P3

UNC Network Management: S1

UNC Network Management: S2

Other Models

OAMP
- Operations
- Administration
- Maintenance
- Provisioning
Time To Call
- monitor
- engineer
- manage

NAT

Network Address Translation
RFC 1631 obsolete, RFC 3022 traditional
- public address routed "in front of" private addresses
  - IPv4 address are somewhat scarce
  - RFC 1918 private addresses aren't
  - aka PAT, Port Address Translation
  - remember that socket pairs are unique ...
  - but headers are modified ... so some applications like (active) ftp break

PAT

or PAT
- multi-homing, load balancing, failover
- inherent incoming security
- (inbound) port forwarding, DMZ
  - see GRC, a venerable security site
- IPSec
- How Skype tunnels through NAT

RFC 1918 (Review)

private, non-routeable, addresses:
- 10.0.0.0/8 or 10.0.0.0 to 10.255.255.255
- 172.16.0.0/12 or 172.16.0.0 to 172.31.255.255
- 192.168.0.0/16 or 192.168.0.0 to 192.168.255.255

Security

authentication
authorization
encryption
don't ship unencrypted private data via insecure transport (including the Internet)
Security Engineering (book)

Privacy

anonymity
free speech? but SSN, voting, income
Scott Bradner: 1 and 2

Centralized Vocabulary Review

a centralized network is a classic tree with a single root
a distributed network is a mesh (full or partial)
a decentralized network is in-between

Client-Server

centralized
central server, many clients
single place to update
updates can be seen on all clients at the right time
web, DNS, most NMS, more

Peer-to-Peer

Wikipedia on P2P: ad hoc
unstructured P2P
- distributed
- Gnutella
- flood queries, poor traffic-to-search efficiency
structured P2P
- decentralized
- CAN uses DHT, Distributed Hash Table
  - Adeona uses OpenDHT

Peer-to-Peer Discussion

no server, but a super-node is a local server
VoIP
- SIP is a standard, SIP phones talk to each other directly
  - Gizmo has Google (GrandCentral) integration, free
  - QuteCom is F/OSS
- Skype
  - P2P from Kazaa, worrisome terms

Peer-to-Peer Discussion

where is BitTorrent?
- tracker is a server, distribution is P2P
- hybrid P2P
Hamachi is zeroconf p2p vpn
- but security
- or just OpenVPN

(Hamachi blurb should make your head spin!)

Take a Deep Breath ...

IPv6 Addresses

128 bits written as 8 hex strings separated by colons
- many more addresses available, not a mere 3 to 4 billion!
leading zeroes can be omitted per string
multiple zeroes can be omitted entirely, but only once in an address

IPv6 Features

no broadcast

different kinds of multicast, some work well (L2, link local), some have problems

no private addresses (but link local with low TTL)
no DHCP (but does have automatic configuration)

IPv4 needs DHCP to use available addresses efficiently

DHCP provides better automatic configuration than BOOTP (its precedessor)

IPv6's larger address space shouldn't need DHCP's efficiency, and auto config should help too.

128-bit addresses (32-bit address space is getting tight)
less-used options in IPv4 header are now optional for less overhead
flow-labeling for QoS
IP Security built-in

IPv6 Header

RFC 2460
4 bits - version (6)
8 bits - traffic class (priority)
20 bits - flow label

IPv6 Header

16 bits - payload length, including optional extension headers (or 0 for jumbo)
8 bits - next header
8 bits - hop limit, like TTL

IPv6 Header

128 bits - source address
128 bits - destination address

IPv6 Scope

link local: LAN only, automatic, unrouted
site local: optional, user assigned, unrouted
global unicast: IANA assigned unique address
multicast: several scopes here too ...
anycast: one-to-nearest, routers only
loopback: local NIC

IPv6 Multicast Scopes

8 bits - routing prefix (fixed)
4 bits - flags - 0000 for IANA or 0001 for transient
4 bits - scope
- 0 & 3 & F reserved
- 1 interface-local scope
- 2 link-local scope
- 4 admin-local scope
- 5 site-local scope
- 8 org-local scope
- E global scope

How Do We Get There From Here?

must translate IPv6 to IPv4
6to4
- What about NAT?
  - use Teredo instead

BONUS: Teredo actually works! (unlike 6to4)

Light Reading

Browse Zytrax on IPv6 to supplement class coverage. Once you can handle the addressing, you're most of the way to understanding IPv6.

Homework

HW04