Client Communication

1
Client Communication

• NIC is Really
• The physical hardware plus
• Software device driver
• Upper-layer software talks to device driver
• Together, implement subnet layer protocols

NIC and Device driver Together handle PHY, MAC,
LLC
Device Driver
NIC
2
Client Communication

• Client PC has Multiple Transport-Internet Layer
  Protocol Stacks for Different Protocols
• NDIS in Windows Governs their Communication with
  the Single NIC

TCP
SPX
IP
IPX
NDIS
3
Client Communication

• NDIS routes incoming packets to correct stack
  (IPX to SPX/IPX, etc.)

TCP
SPX
IP
IPX
NDIS
4
Client Communication

• NDIS feeds outgoing packets one at a time to the
  NIC

TCP
SPX
IP
IPX
NDIS