Transcript IP LAB: Current Architecture

Implementation and Evaluation of a
Performance Enhancing Proxy for Wireless
TCP
Scenarios and Architecture
Scenarios of interest
Definition Scenario:
Every time, hardware changes (including configurations) have to be
done, a new scenario is created.
Meta-Modell for Scenarios
• ??????
Classification
Classify Scenarios in different Classes:
• Wired
• Wireless
– Local (fixed IP)
– Mobile
• Handover Access Points
• Handover Access Techniques
Standard Wired Scenarios
”Wired World”
Client
Server
(e.g. HTTP, FTP)
Possible Scenarios:
• Server & Client in same net (LAN), client-serverpath known and traffic „stable/static“
• Wired World = Internet, Client & Server in
different subnets, path unknown, traffic variable,
more congestion
Fixed wireless Scenario
Wired World
WLAN AP
Server (e.g.
HTTP, FTP)
Possible Scenarios:
• Server in same/different subnet as Client
• High BER
• Signal loss, reconnect
Mobile Wireless Scenario (Access Points)
Wired World
Server (e.g.
HTTP, FTP)
WLAN AP
Handover
WLAN AP
Possible Scenarios:
• AP‘s same/different subnet
• Server & Client same/different subnet
Mobile Wireless Scenarios (Access Techniques)
Wired World
Server (e.g.
HTTP, FTP)
WLAN AP
Handover
GPRS AP
Possible Scenarios:
• WLAN -> GPRS -> WLAN
• WLAN -> UMTS -> WLAN
• WLAN -> Bluetooth -> WLAN
• .....
Current Network Architecture
IP LAB: Current Architecture
WLAN AP
Switch
WLAN
(802.11)
Router
A
Router
B
WLAN AP
Router
C
D
WLAN AP
WLAN AP
Internet
Router
E
Router
GPRS
Network
Wired access
(Ethernet)
Server (e.g. Video
application)
Cellular access
(GPRS)
Meta-modell for Network Architectures
Meta-Network-Modell
”Wireless World”
”Wired World”
TCP Proxy
Server
(e.g. HTTP, FTP)
Possible Network Architectures
Classification of Architectures
• Intercepting
– In-Path
– Router-Config
– Gartious ARP
• Forced (Terminologie??)
– IP-Tunneling
– IP-Header-Modification
Full Intercepting Proxy Network Design
WLAN AP 1
Router
Switch
TCP Proxy
Router
A
Intranet
StudNet
B
Terminal
WLAN AP 2
Router
C
D
WLAN AP 3
Router
TCP Proxy
TCP Proxy
E
Switch
WLAN AP 4
Internet
Router
GPRS
Wired World
TCP Proxy
Network
Cellular access
(GPRS)
Client
Server
(e.g. HTTP, FTP)
Wireless World
Possible Scenarios in Full Intercepting
• Server -> Switch -> Client
• Server -> Switch -> TCP Proxy -> WLAN
AP 3-> Client
• Server -> Switch -> Routers -> Switch ->
TCP Proxy -> WLAN AP 1 -> Client
• Server -> Switch -> Routers -> TCP Proxy
-> Internet -> Intranet -> Terminal
• Handover WLAN AP 1 -> WLAN AP 2
• Handover WLAN AP 2 -> WLAN AP 3
• Handover WLAN AP 3 -> WLAN AP 4
• Handover WLAN AP -> GPRS
Problems of Full Intercepted Proxy Scenario
• Hardware efforts (4 Proxies) -> reduction
to max. 2 proxy PC‘s for handover
possible => reconfig for every Scenario
needed
• Internal Server access by Port-Forwarding
• How to realize GPRS handover (Server IP
change from internal to external IP
needed, use Mobile IP??)
Improved Intercepting Proxy Network Design
Router
Switch
A
Client
Router
Intranet
B
StudNet
Router
Terminal
C
Server
(e.g. HTTP, FTP)
D
Router
E
Router
Wired World
TCP Proxy
WLAN AP 1
Internet
Wireless World
Switch
Switch
WLAN AP 2
Switch
IMPOSSIBLE
WLAN AP 3
GPRS
Network
WLAN AP 4
Cellular access
(GPRS)
Forced Proxy Scenarios
WLAN AP 1
Router
Switch
Router
A
Intranet
StudNet
B
Terminal
WLAN AP 2
Router
C
D
WLAN AP 3
Internet
Router
TCP Proxy
E
Router
Switch
WLAN AP 4
Wired World
GPRS
Network
Client
Server
(e.g. HTTP, FTP)
Wireless World
Problems of Forced Proxy Solution
• How to implement forced Proxy? Possible
Solutions:
– „TCP packet in TCP packet“-solution (IPTunneling)
– Modifying TCP packet: Target IP in Optional
field, Proxy IP in Dest. Field
• How to access internal Proxy from outside
world (New TCP Proxy protocol on new
port + port forwarding)?
• More network traffic, evtl. More hops
• GPRS problem not resolved (MobileIP)
Router Config Proxy Scenarios
Wireless World
WLAN AP 1
Wired World
Router
Switch
Intranet
Router
A
StudNet
B
WLAN AP 2
Terminal
Router
C
Internet
WLAN AP 3
D
Router
TCP Proxy
Switch
WLAN AP 4
E
Router
GPRS
Network
Cellular access
(GPRS)
Mixed World
Client
Server
(e.g. HTTP, FTP)
Mixed World
Automated Forced Proxy Network Design
• Idea:
– Categorize every port on router in „wireless,
wired, (evtl. Mixed?)“
– Force router to send packets from wireless to
wired over TCP Proxy ( send from Mixed or to
Mixed always over TCP proxy)
• Problems:
– Is this possible?
– How to force WLAN AP 3 & 4 to use Proxy?
Functional Architecture
„Implementation Plan“
Functional Implementation
WLAN AP 3
Switch
Terminal
StudNet
TCP Proxy
WLAN AP 4
E
Client
Router
Server
(e.g. HTTP, FTP)
Internet
D
• Router Config
• ARP to catch all packets
Intranet
Router
GPRS
Network
Cellular access
(GPRS)