Code,Packet Type,Reference,Note
0,Vendor Specific,[RFC2153],
1,Configure-Request,[RFC1661],
2,Configure-Ack,[RFC1661],
3,Configure-Nak,[RFC1661],
4,Configure-Reject,[RFC1661],
5,Terminate-Request,[RFC1661],
6,Terminate-Ack,[RFC1661],
7,Code-Reject,[RFC1661],
8,Protocol-Reject,[RFC1661],LCP Only
9,Echo-Request,[RFC1661],LCP Only
10,Echo-Reply,[RFC1661],LCP Only
11,Discard-Request,[RFC1661],LCP Only
12,Identification,[RFC1570],LCP Only
13,Time-Remaining,[RFC1570],LCP Only
14,Reset-Request,[RFC1962],CCP Only
15,Reset-Reply,[RFC1962],CCP Only