166
C
HAPTER
12: C
ONFIGURING
PPP
AND
MP
The authenticator sends some randomly generated packets to the requester
(challenge), and at the same time it sends its configured username to the
requester.
When the requester receives the challenge, it will look for the user password
according to the authenticator's username and its own user list. If it finds the user
in the user list with the same name as the authenticator's username, the requester
builds the response with its own password, serial number of packet using MD5
algorithm, and sends the generated response and its configured username to the
authenticator (response).
After receiving the response from the requester, the authenticator does the same
encryption as the requester with the saved password, serial number of packet
using MD5 algorithm. Then it compares the encryption result with the response
from requester, and returns the response according to the comparison result
(Acknowledge or Not Acknowledge).
3
Phases of PPP negotiation:
a
When the physical layer is unavailable, the link is in Dead phase. A link shall start
from the Dead phase. When the physical layer becomes available, PPP link enters
the Establish phase.
b
In
Establish
phase, PPP link carries out LCP negotiation, including negotiation
of working mode (SP or MP), authentication mode and maximum transmission
unit etc. After the successful LCP negotiation, the status of LCP is
Open
,
indicating that the link has been established.
c
If the authentication is not configured, it begins NCP negotiation. At this time,
the status of LCP is still
Open
, while the status of NCP is changed from
Initial
to
Request-sent
.
d
If the authentication is configured (the remote verifies the local or the local
verifies the remote), it enters
Authenticate
phase to start CHAP or PAP
authentication. If the authentication fails, it enters
Terminate
phase, the link is
removed and LCP turns down. After successful authentication, the NCP
negotiation begins. At this time, the status of LCP is still
Open
, while the status
of NCP is changed from Initial to
Request-sent
.
e
NCP negotiation supports the negotiations of IPCP and IPXCP, of which IPCP
negotiation mainly includes the IP addresses of two partners. One or more
network layer protocols is selected and configured through NCP negotiation.
The selected network layer protocol must be configured successfully before this
network layer protocol sends packets through this link.
f
PPP link will remain in communication status until a specific LCP or NCP frame
closes this link or some external events take place (for example, the
intervention of user).
Phases of PPP negotiation are shown in the following diagram.
Summary of Contents for 3036
Page 1: ...http www 3com com 3Com Router Configuration Guide Published March 2004 Part No 10014299 ...
Page 4: ...VPN 615 RELIABILITY 665 QOS 681 DIAL UP 721 ...
Page 6: ...2 ABOUT THIS GUIDE ...
Page 7: ...I GETTING STARTED Chapter 1 3Com Router Introduction Chapter 2 3Com Router User Interface ...
Page 8: ...4 ...
Page 16: ...12 CHAPTER 1 3COM ROUTER INTRODUCTION ...
Page 34: ...30 ...
Page 60: ...56 CHAPTER 3 SYSTEM MANAGEMENT ...
Page 98: ...94 CHAPTER 6 DISPLAY AND DEBUGGING TOOLS ...
Page 110: ...106 ...
Page 114: ...110 CHAPTER 8 INTERFACE CONFIGURATION OVERVIEW ...
Page 158: ...154 CHAPTER 10 CONFIGURING WAN INTERFACE ...
Page 168: ...164 ...
Page 188: ...184 CHAPTER 13 CONFIGURING PPPOE CLIENT ...
Page 192: ...188 CHAPTER 14 CONFIGURING SLIP Router ip route static 0 0 0 0 0 0 0 0 10 110 0 1 ...
Page 248: ...244 CHAPTER 16 CONFIGURING LAPB AND X 25 ...
Page 320: ...316 ...
Page 330: ...326 CHAPTER 20 CONFIGURING IP ADDRESS ...
Page 362: ...358 CHAPTER 21 CONFIGURING IP APPLICATION ...
Page 374: ...370 CHAPTER 23 CONFIGURING IP COUNT ...
Page 406: ...402 CHAPTER 25 CONFIGURING DLSW ...
Page 408: ...404 ...
Page 452: ...448 CHAPTER 29 CONFIGURING OSPF ...
Page 482: ...478 CHAPTER 30 CONFIGURING BGP ...
Page 494: ...490 CHAPTER 31 CONFIGURING IP ROUTING POLICY ...
Page 502: ...498 ...
Page 508: ...504 CHAPTER 33 IP MULTICAST ...
Page 514: ...510 CHAPTER 34 CONFIGURING IGMP ...
Page 526: ...522 CHAPTER 36 CONFIGURING PIM SM ...
Page 528: ...524 ...
Page 532: ...528 CHAPTER 37 CONFIGURING TERMINAL ACCESS SECURITY ...
Page 550: ...546 CHAPTER 38 CONFIGURING AAA AND RADIUS PROTOCOL ...
Page 590: ...586 CHAPTER 40 CONFIGURING IPSEC ...
Page 599: ...IX VPN Chapter 42 Configuring VPN Chapter 43 Configuring L2TP Chapter 44 Configuring GRE ...
Page 600: ...596 ...
Page 638: ...634 CHAPTER 43 CONFIGURING L2TP ...
Page 649: ...X RELIABILITY Chapter 45 Configuring a Standby Center Chapter 46 Configuring VRRP ...
Page 650: ...646 ...
Page 666: ...662 ...
Page 670: ...666 CHAPTER 47 QOS OVERVIEW ...
Page 700: ...696 CHAPTER 49 CONGESTION MANAGEMENT ...
Page 706: ...702 CHAPTER 50 CONGESTION AVOIDANCE ...
Page 707: ...XII DIAL UP Chapter 51 Configuring DCC Chapter 52 Configuring Modem ...
Page 708: ...704 ...
Page 762: ...758 CHAPTER 52 CONFIGURING MODEM ...