CCENT 6 S01 E28 – WAN Connectivity

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Abbreviations
Understanding the categories of WAN connections
Layer 2 WAN Protocols
Configuring HDLC and PPP WAN Connections

 

Abbreviations

CSU/DSU: Channel Service Unit/Data Service Unit
DCE / DTE: Data Communication Equipment (clock)/ Data Terminal Equipment
DLCI: (Delsy) Data Link Connection Identifier
HDLC: High-level Data Link Control (Cisco Proprietary)
PPP: Point to Point Protocol
WAN: Wide Area Network

Definition

Wan provides connectivity between offices

  • Could be within same city
  • Could be several thousands of miles apart.

Categories of WAN Connectivity

  • Layer 1: Instead of RJ45, WAN uses Serial physical connections
  • Layer 2: No MAC addresses, but uses
    • Frame Relay: Not just a connection type, but also a protocol. DLCI (Delsy) Datalink Connection Identifier)
    • ATM, PPP, HDLC, and many more.
  • Primary Considerations
    • Price
    • Speed

Styles of WAN Connections

Leased Lines: Dedicated Bandwidth between locations

  • T1 CAS
    • T1= 1.544 Mbps
    • Dedicated bandwidth
    • Most expensive

Circuit Switched: On-demand Bandwidth between locations

  • Dial-Up Modems
  • ISDN
  • Low Price
  • Low Bandwidth

Packet Switched: Shared, but guaranteed, bandwidth between locations

  • Frame Relay
  • ATM
  • X25 (older, no common in US)

Configuring Leased Line Connections

These are Layer 2 Protocols

HDLC: Highlevel Data Link Control

  • Cisco Proprietary (Both sides must be Cisco)
  • Plug it in and it works.

PPP: Point to Point Protocol

  • Most common used. Works with all equipment mfgs

Configure PPP

r1(config)#interface serial 0/1
r1(config-if)#encapsulation ppp
r1(config-if)#clock
r2(config)#interface serial 0/0
r2(config-if)#encapsulation ppp

Show Commands

show controllers serial 0/0

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