Remote Peer Scenarios During Negotiation of PPP Options

During a PPP configuration request, if any of the primary or secondary DNS option is rejected, or if they are unacceptable, the CPE (Customer Premises Equipment) is prompted to negotiate the IPCP primary and secondary DNS options that are locally available with the B-RAS (Broadband Remote Access Server). This provision is controlled by CLI and SNMP configuration options.

The following describes the peer negotiations in different scenarios:

• The CPE does not send the prompted options in the subsequent configure request
  • If B-RAS sends another NAK, it prompts the options again, until max configure-nak is exceeded
  • If B-RAS sends an ACK, it ignores the options and brings up the link
• The CPE negotiates a different option from the prompted options
  • If B-RAS sends another NAK, it prompts the options again, until max configure-nak is exceeded
  • If B-RAS sends an ACK, it ignores the options and brings up the link
• The CPE negotiates the prompted options but the option values are not acceptable
  • B-RAS sends another NAK with the prompted options, until max configure-nak is exceeded
• The CPE negotiates the prompted options but some option values are not acceptable
  • B-RAS sends a NAK for unacceptable options, until max configure-nak is exceeded
• The CPE stops responding on receiving the prompted options
  • B-RAS negotiation timer expires and the link is terminated
• The CPE negotiates the prompted option after the link comes up
  • This is treated as a renegotiation request and B-RAS sends an ACK/NAK until max renegotiation and max configure-nak counters are exceeded, respectively
• The CPE starts renegotiation without the prompted options
  • B-RAS renegotiates, until max renegotiation is exceeded
  • If B-RAS sends a NAK, it prompts the options, until max configure-nak is exceeded
  • If B-RAS sends an ACK, it ignores the options and brings up this link
• The CPE NAKs or rejects the prompted options
  • This behavior is non-compliant with RFC because a configure-rej or a configure-nak must be sent only in response to a configure-req

Related Documentation

• Understanding Extensible Authentication Protocol
• Broadband Remote Access Support for PPP Overview