Wednesday 11 December 2013

Cisco WAAS (Basic concepts)

Watch the complete Video of this section -


WAAS is a symmetric solution requiring a WAAS component on both sides of the conversation. Peer-to-peer. WAN traffic between WAAS components is highly optimized while still visible to QoS/Management applications

WAAS devices auto-discover each other without any user intervention allowing optimization not only to the data center but between WAAS enabled branches



The WAAS administrator can classify which WAN traffic should be optimized based on criteria such as protocol (port number), source and/or destination IP address and/or network. 

WAAS Overview Application Acceleration Transparency
Packet network transparency (L3/L4 headers) allows application acceleration components to maintain compliance with existing network features

WAAS Overview TFO Auto-Discovery – TCP SYN
When the client sends a TCP-SYN packet, WAE1 will apply TCP options to identify itself and specify the optimizations that it would like to apply
The modified TCP-SYN packet is then forwarded to the server, and intercepted on the other side 



WAAS Overview TFO Auto-Discovery – TCP SYN (Cont.)
Once WAE2 receives the TCP-SYN packet with the options marked, it then knows WAE1’s details and desire to optimize this connection
The TCP-SYN packet is then forwarded to the server 

WAAS Overview TFO Auto-Discovery – TCP SYN-ACK
When the server responds with the TCP SYN-ACK, WAE2 then marks TCP options to acknowledge optimization and to identify itself to WAE1
The marked TCP SYN-ACK packet is then forwarded towards the client and intercepted on the other side

WAAS Overview TFO Auto-Discovery – TCP SYN-ACK (Cont.)
When WAE1 receives the TCP SYN-ACK with the optimization confirmation and details about WAE2, the defined policy (or negotiated optimizations) can then be acknowledged
The TCP SYN-ACK packet is then forwarded to the client 
WAAS Overview TFO Auto-Discovery – TCP ACK
After the SYN-ACK is received, the TCP proxy is initiated for the connection, and WAE1 sends a TCP ACK to WAE2 to acknowledge optimizations
WAE2 can then send a TCP ACK to Server B

Client A sends a TCP ACK to WAE1





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