DLSW

DLSW

Developed to carry LLC2 frames across a TCP/IP network
  • DSLWv1 developed in 1995
  • DSLWv2 developed in 1997 (Scalability and redundancy)
  • DSLW+ Cisco’s implementation
Better than transparent bridging
  • Local acknowledgements
  • higher availability
  • load balancing
 
IEEE 802.2 LLC Type 2 assumed that the network delay was small and predictable. When delay occurs, timeouts begin to happen and frames are retransmitted. Causes duplicate packets to be received by the mainframe.
Client to mainframe, DLSW terminates LLC2 at the router, and an acknowledgement is sent to the client.
 
Search frames (allows clients to locate server) are no longer flooded after the router locates the end device. Router will cache.
 
Neighboring routers are referred to as peers
Once supported protocol makes a connection, it is called a peer connection
Protocols support
  • SNA PU Type 2.0/2.1/4
  • SDLC PU1 Type 1-4
  • NETBIOS
  • NETBEUI
DLSW Encapsulation Options
  • TCP Encapsulation - (Most common, most features, but most overhead)
  • FST Encapsulation - low overhead, supports any WAN type, no reliability. Only supports Token Ring source.
  • Direct Encapsulation - low overhead, only supports Token Ring source, only supports HDLC & Frame Relay
  • LLC2 Encapsulation (DLSW LITE) - Frame relay only
 
DLSW Locates resources
  1. Client generates a request for MAC address
  1. Router generates CanYouReach Frame
  1. Peer responds with ICanReach
  1. Circuit is established
  1. Router caches MAC address
 
DLSW Configuration
  1. (Optional) use loopback interfaces for redundant connections
  1. Create the DLSW local peer
  1. Enable bridging on required interfaces and link to DLSW
  1. Choose peer encapsulation and configure remote peer
 
bridge 1 protocol ieee

int e0
	bridge-group 1
	
dlsw local-peer peer-id 170.100.100.2
dlsw remote-peer 0 tcp 170.100.100.3
dlsw bridge-group 1

show dlsw peers
show dlsw reachability
show dlsw circuits