이더넷 (Ethernet)

작성자
조재혁 (minzkn@minzkn.com)
고친과정
2008년 9월 1일 : 처음씀

1.1. 용어정의
1.2. Ethernet frame
1.3. ARP packet 구조
1.4. Linux에서 Ethernet frame 수신해보기
1.5. 2008년 9월 1일 현재 IANA ethernet-numbers
1.6. 참고자료

1.1. 용어정의

SFD : Start of Frame Delimiter
DA : Destination MAC address
SA : Source MAC address
ToL : Type or Length
FCS : Frame Check Sequence
CRC : Cyclic Redundancy Check
LLC : Logical Link Control
DSAP : Destination Service Access Point
SSAP : Source Service Access Point
NIC : Network Interface Card
SNAP : SubNetwork Access Protocol

7 parts of an Ethernet Frame
참고 영상

[Youtube movie]

데이터 링크 계층, MAC 주소 지정 및 이더넷 프레임
참고 영상

[Youtube movie]

7 parts of an Ethernet Frame
참고 영상
[Youtube movie]

데이터 링크 계층, MAC 주소 지정 및 이더넷 프레임
참고 영상
[Youtube movie]

1.2. Ethernet frame

Preamble, 10101010B x 7 (7 octets)	SFD, 10101011B (1 octet)	DA(6 octets)	SA(6 octets)	802.1Q/802.1p tag (4 octets, optional)	ToL(2 octets) : Ethertype (Ethernet II) or length (IEEE 802.3)	Payload(46~1500 octets)	Frame check sequence (4 octets, 32bits CRC)	Interpacket gap (12 octets)
		← Layer 2 Ethernet frame (64(68) ~ 1518(1522) octets) →						← Layer 1 (12octets) →
← Layer 1 Ethernet packet & IPG (72(76) ~ 1526(1530) octets) →

Payload 부분이 46octets 보다 작은경우 46octets가 되도록 0으로 Pad합니다.
MAC address의 구조는 다음과 같이 제조회사 ID와 NIC ID로 구성됩니다.

제조회사 ID (3 octets) NIC ID (3 octets)

ToL(Type or Length)의 값이 0x0600이상인 경우 Type으로 사용되며 미만인경우 Length로 사용됩니다. 즉, 0x0600이상인 경우 Ethernet v2 frame이 되며 미만인 경우 IEEE 802.3 frame 이 됩니다.

Ethernet v2 frame (RFC894, DIX 2.0)

Preamble, 10101010B x 7 (7 octets)

SFD, 10101011B (1 octet)

DA(6 octets)

SA(6 octets)

Type (2 octets)

Data unit + Pad (46~1500 octets)

Frame check sequence (4 octets, 32bits CRC)

Type (참고: http://www.iana.org/assignments/ethernet-numbers)

IEEE 802.3 frame

Preamble, 10101010B x 7 (7 octets)

SFD, 10101011B (1 octet)

DA(6 octets)

SA(6 octets)

Length (2 octets)

802.2 LLC + Data unit + Pad (46~1500 octets)

Frame check sequence (4 octets, 32bits CRC)

802.2 LLC
DSAP(1 octet) SSAP(1 octet) Control(1 or 2 octets) LLC Information
- DSAP값 정의 (값이 AAH인 경우 802.2 LLC뒤에 802.2 SNAP가 붙습니다.)
  
  값 종류
  
  06H IP
  
  42H BPDU
  
  7EH X.25 PLP
  
  80H XNS
  
  E0H Netware IPX
  
  F0H NetBIOS
  
  FFH Global SAP
  
  AAH IEEE SNAP
802.2 SNAP
OUI (3 octets) Protocol Identifier (2 octets)
- OUI (3 octets) : NIC 제조회사를 식별하는 값 (현재는 대부분 000000H이 많습니다.)
  - 값이 0080C2H이면 Protocol Identifier에 따라 MAC bridge에서 사용합니다.
  - 값이 000000H이면 Protocol Identifier를 확인하여 해당 protocol로 demultiplexing합니다.
- Protocol Identifier : 상위 protocol을 지정하는 부분으로 Ethernet v2(DIX 2.0) frame의 Type과 같은 역할을 합니다.

FCS(Frame check sequence)는 DA(Destination MAC address) + SA(Source MAC address) + ToL(Type or Length) + Payload 를 CRC계산한 값입니다.

1.3. ARP packet 구조

Ethernet frame의 ToL(Type of Length)값이 0806H또는 0835H인경우 ARP packet입니다.

Hardware Type(16bits)

Protocol Type(16bit)

Hardware Length(8bits)

Protocol Length(8bits)

Operation(16bits)

Sender(Source) Hardware address(Hardware Length)

Sender(Source) Protocol address (Protocol Length)

Target(Destination) Hardware Address (Hardware Length)

Target(Destination) Protocol Address (Protocol Length)

Hardware Type ( [http]

http://www.iana.org/assignments/arp-parameters/arp-parameters.xml

)

값	설명
0	Reserved
1	Ethernet (10Mb)
2	Experimental Ethernet (3Mb)
3	Amateur Radio AX.25
4	Proteon ProNET Token Ring
5	Chaos
6	IEEE 802.3 networks
7	ARCNET
8	Hyperchannel
9	Lanstar
10	Autonet Short Address
11	LocalTalk
12	LocalNet (IBM PCNet or SYTEK LocalNET)
13	Ultra link
14	SMDS
15	Frame Relay
16	Asynchronous Transmission Mode (ATM)
17	HDLC
18	Fibre Channel
19	Asynchronous Tramsmission Mode (ATM)
20	Serial Line
21	Asynchronous Tramsmission Mode (ATM)
22	MIL-STD-188-220
23	Metricom
24	IEEE 1394.1995
25	MAPOS
26	Twinaxial
27	EUI-64
28	HIRARP
29	IP and ARP over ISO 7816-3
30	ARPSec
31	IPsec tunnel
32	InfiniBand (TM)
33	TIA-102 Project 25 Common Air Interface (CAI)
34	Wiegand Interface
35	Pure IP
36	HW_EXP1
37	HFI
38~255	Unassigned
256	HW_EXP2
257~65534	Unassigned
65535	Reserved

Protocol Type : Mapping 대상의 유형을 나타냅니다. (IPv4의 경우는 0x0800 으로 설정할 수 있습니다.)
Operation

값 설명

1 ARP Request

2 ARP Reply

3 RARP Request

4 RARP Reply

1.4. Linux에서 Ethernet frame 수신해보기

아래의 예제는 Linux에서 Ethernet packet을 수신해보는 예제입니다. RAW socket을 이용하기 때문에 반드시 root 유저권한에서 실행해야 올바른 수신이 됩니다.

More

#include <sys/types.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <time.h>

#include <netinet/in.h>

#include <linux/if_ether.h>
#include <linux/if_packet.h>

#if 1 && (!defined(mz_dump))
#include <stdio.h>
static void * (__mz_dump_ex__)(size_t s_s, size_t s_d, void * s_da, size_t s_si)
{ size_t s_o, s_w, s_lo; unsigned char s_b[ 16 + 1 ];
 if(s_da == NULL)return(NULL); s_b[sizeof(s_b) - 1] = (unsigned char)'\0';
 for(s_o = (size_t)0;s_o < s_si;s_o += (size_t)16){
  s_w = ((s_si - s_o) <= ((size_t)16)) ? (s_si - s_o) : ((size_t)16);
  (void)fprintf(stdout, "%08lX", (unsigned long)(s_d + s_o));
  for(s_lo = (size_t)0;s_lo < s_w;s_lo++){
   if(s_lo == ((size_t)(16 >> 1)))(void)fputs(" | ", stdout);
   else (void)fputs(" ", stdout);
   s_b[s_lo] = *(((unsigned char *)s_da) + (s_s + s_o + s_lo));
   (void)fprintf(stdout, "%02X", (int)s_b[s_lo]);
   if((s_b[s_lo] & ((unsigned char)(1 << 7))) || (s_b[s_lo] < ((unsigned char)' ')) ||
      (s_b[s_lo] == ((unsigned char)0x7f)))s_b[s_lo] = (unsigned char)'.';}
  while(s_lo < ((size_t)16)){
   if(s_lo == ((size_t)(16 >> 1)))(void)fputs("     ", stdout);
   else (void)fputs("   ", stdout);
   s_b[s_lo] = (unsigned char)' '; s_lo++;}
  (void)fprintf(stdout, " [%s]\n", (char *)(&s_b[0]));}
 return(s_da);
}
static __inline void * (mz_dump_ex)(size_t s_seek_offset, size_t s_display_offset, void * s_data, size_t s_size)
{ return(__mz_dump_ex__(s_seek_offset, s_display_offset, s_data, s_size)); }
#define mz_dump(m_data,m_size) mz_dump_ex((size_t)0,(size_t)0,(void *)(m_data),(size_t)(m_size))
#endif

int main(void)
{
    uint8_t s_buffer[ 4 << 10 ];
    int s_socket;
    ssize_t s_recv_bytes;

#if 0L
    s_socket = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
#else
    s_socket = socket(PF_INET, SOCK_PACKET, htons(ETH_P_ALL));
#endif
    if(s_socket == (-1)) {
        perror("socket");
        return(EXIT_FAILURE);
    }

#if 0L /* 특정 interface만 수신하고자 할때 */
    do {
        struct sockaddr s_sockaddr;
        static const char *cg_interface_name = "eth0";

        (void)memset((void *)(&s_sockaddr), 0, sizeof(s_sockaddr));
        (void)strncpy((char *)s_sockaddr.sa_data, cg_interface_name, sizeof(s_sockaddr.sa_data));
        if(bind(s_socket, (struct sockaddr *)(&s_sockaddr), (socklen_t)sizeof(s_sockaddr)) == (-1)) {
            perror("bind");
            return(EXIT_FAILURE);
        }
    }while(0);
#endif

    for(;;) {
        s_recv_bytes = recv(s_socket, (void *)(&s_buffer[0]), sizeof(s_buffer));
        if(s_recv_bytes <= ((ssize_t)0)) {
            continue;
        }

        mz_dump(&s_buffer[0], s_recv_bytes);
        /* 
        ...
        */
    }

    while((close(s_socket) == (-1)) && (errno == EINTR));

    return(EXIT_SUCCESS);
}

1.5. 2008년 9월 1일 현재 IANA ethernet-numbers

More

Ether Types

(last updated 2008-08-27)

NOTE: Please see [RFC-eastlake-ethernet-iana-considerations-08.txt] for current
information and registration procedures. This registry will be revised soon and
will be replaced with up-to-date information.

Many of the networks of all classes are Ethernets (10Mb) or
Experimental Ethernets (3Mb).  These systems use a message "type"
field in much the same way the ARPANET uses the "link" field.

If you need an Ether Type, contact:

IEEE Registration Authority
IEEE Standards Department
445 Hoes Lane
Piscataway, NJ 08854
Phone +1 732 562 3813
Fax: +1 732 562 1571
Email: <ieee-registration-authority&ieee.org>
http://standards.ieee.org/regauth/index.html


The following list of EtherTypes is contributed unverified information
from various sources.  Another list of EtherTypes is maintained by
Michael A. Patton and is accessible at:

    <URL:http://www.cavebear.com/CaveBear/Ethernet/>
    <URL:ftp://ftp.cavebear.com/pub/Ethernet-codes>


Assignments:

Ethertype         Exp. Ethernet   Description           References
-------------     -------------   -----------           ----------
decimal  Hex      decimal  octal
  0000   0000-05DC   -       -    IEEE802.3 Length Field   [XEROX]
  0257   0101-01FF   -       -    Experimental             [XEROX]  
  0512   0200        512   1000   XEROX PUP (see 0A00)   [8,XEROX]
  0513   0201        -      -     PUP Addr Trans (see 0A01)[XEROX]
         0400                     Nixdorf                  [XEROX]
  1536   0600       1536   3000   XEROX NS IDP         [133,XEROX]
         0660                     DLOG                     [XEROX]
         0661                     DLOG                     [XEROX]
  2048   0800        513   1001   Internet IP (IPv4)        [IANA]
  2049   0801        -      -     X.75 Internet            [XEROX]
  2050   0802        -      -     NBS Internet             [XEROX]
  2051   0803        -      -     ECMA Internet            [XEROX]
  2052   0804        -      -     Chaosnet                 [XEROX]
  2053   0805        -      -     X.25 Level 3             [XEROX]
  2054   0806        -      -     ARP                       [IANA]
  2055   0807        -      -     XNS Compatability        [XEROX]
  2056   0808        -      -     Frame Relay ARP        [RFC1701]
  2076   081C        -      -     Symbolics Private         [DCP1]
  2184   0888-088A   -      -     Xyplex                   [XEROX]
  2304   0900        -      -     Ungermann-Bass net debugr[XEROX]
  2560   0A00        -      -     Xerox IEEE802.3 PUP      [XEROX]
  2561   0A01        -      -     PUP Addr Trans           [XEROX]
  2989   0BAD        -      -     Banyan VINES             [XEROX]
  2990   0BAE        -      -     VINES Loopback         [RFC1701]
  2991   0BAF        -      -     VINES Echo             [RFC1701]
  4096   1000        -      -     Berkeley Trailer nego    [XEROX]
  4097   1001-100F   -      -     Berkeley Trailer encap/IP[XEROX]
  5632   1600        -      -     Valid Systems            [XEROX]
 16962   4242        -      -     PCS Basic Block Protocol [XEROX]
 21000   5208        -      -     BBN Simnet               [XEROX]
 24576   6000        -      -     DEC Unassigned (Exp.)    [XEROX]
 24577   6001        -      -     DEC MOP Dump/Load        [XEROX]
 24578   6002        -      -     DEC MOP Remote Console   [XEROX]
 24579   6003        -      -     DEC DECNET Phase IV Route[XEROX]
 24580   6004        -      -     DEC LAT                  [XEROX]
 24581   6005        -      -     DEC Diagnostic Protocol  [XEROX]
 24582   6006        -      -     DEC Customer Protocol    [XEROX]
 24583   6007        -      -     DEC LAVC, SCA            [XEROX]
 24584   6008-6009   -      -     DEC Unassigned           [XEROX]
 24592   6010-6014   -      -     3Com Corporation         [XEROX]
 25944   6558        -      -     Trans Ether Bridging   [RFC1701]
 25945   6559        -      -     Raw Frame Relay        [RFC1701]
 28672   7000        -      -     Ungermann-Bass download  [XEROX]
 28674   7002        -      -     Ungermann-Bass dia/loop  [XEROX] 
 28704   7020-7029   -      -     LRT                      [XEROX]
 28720   7030        -      -     Proteon                  [XEROX]
 28724   7034        -      -     Cabletron                [XEROX]
 32771   8003        -      -     Cronus VLN            [131,DT15]
 32772   8004        -      -     Cronus Direct         [131,DT15]
 32773   8005        -      -     HP Probe                 [XEROX]
 32774   8006        -      -     Nestar                   [XEROX]
 32776   8008        -      -     AT&T                     [XEROX]
 32784   8010        -      -     Excelan                  [XEROX]
 32787   8013	     -      -     SGI diagnostics            [AXC]
 32788   8014        -      -     SGI network games          [AXC]
 32789   8015        -      -     SGI reserved               [AXC]
 32790   8016	     -      -     SGI bounce server          [AXC]
 32793   8019        -      -     Apollo Domain            [XEROX]
 32815   802E        -      -     Tymshare                 [XEROX]
 32816   802F        -      -     Tigan, Inc.              [XEROX]
 32821   8035        -      -     Reverse ARP             [48,JXM]
 32822   8036        -      -     Aeonic Systems           [XEROX]
 32824   8038        -      -     DEC LANBridge            [XEROX]
 32825   8039-803C   -      -     DEC Unassigned           [XEROX]
 32829   803D        -      -     DEC Ethernet Encryption  [XEROX]
 32830   803E        -      -     DEC Unassigned           [XEROX]
 32831   803F        -      -     DEC LAN Traffic Monitor  [XEROX]
 32832   8040-8042   -      -     DEC Unassigned           [XEROX]
 32836   8044        -      -     Planning Research Corp.  [XEROX]
 32838   8046        -      -     AT&T                     [XEROX]
 32839   8047        -      -     AT&T                     [XEROX]
 32841   8049        -      -     ExperData                [XEROX]   
 32859   805B        -      -     Stanford V Kernel exp.   [XEROX]
 32860   805C        -      -     Stanford V Kernel prod.  [XEROX]
 32861   805D        -      -     Evans & Sutherland       [XEROX]
 32864   8060        -      -     Little Machines          [XEROX]
 32866   8062        -      -     Counterpoint Computers   [XEROX]
 32869   8065        -      -     Univ. of Mass. @ Amherst [XEROX]
 32870   8066        -      -     Univ. of Mass. @ Amherst [XEROX]
 32871   8067        -      -     Veeco Integrated Auto.   [XEROX]
 32872   8068        -      -     General Dynamics         [XEROX]
 32873   8069        -      -     AT&T                     [XEROX]
 32874   806A        -      -     Autophon                 [XEROX]
 32876   806C        -      -     ComDesign                [XEROX]
 32877   806D        -      -     Computgraphic Corp.      [XEROX]
 32878   806E-8077   -      -     Landmark Graphics Corp.  [XEROX]
 32890   807A        -      -     Matra                    [XEROX]
 32891   807B        -      -     Dansk Data Elektronik    [XEROX]
 32892   807C        -      -     Merit Internodal           [HWB]
 32893   807D-807F   -      -     Vitalink Communications  [XEROX]
 32896   8080        -      -     Vitalink TransLAN III    [XEROX]
 32897   8081-8083   -      -     Counterpoint Computers   [XEROX]
 32923   809B        -      -     Appletalk                [XEROX]
 32924   809C-809E   -      -     Datability               [XEROX]
 32927   809F        -      -     Spider Systems Ltd.      [XEROX]
 32931   80A3        -      -     Nixdorf Computers        [XEROX]
 32932   80A4-80B3   -      -     Siemens Gammasonics Inc. [XEROX]
 32960   80C0-80C3   -      -     DCA Data Exchange Cluster[XEROX]
 32964   80C4        -      -     Banyan Systems           [XEROX]
 32965   80C5        -      -     Banyan Systems           [XEROX]
 32966   80C6        -      -     Pacer Software           [XEROX]
 32967   80C7        -      -     Applitek Corporation     [XEROX]
 32968   80C8-80CC   -      -     Intergraph Corporation   [XEROX]
 32973   80CD-80CE   -      -     Harris Corporation       [XEROX]
 32975   80CF-80D2   -      -     Taylor Instrument        [XEROX]
 32979   80D3-80D4   -      -     Rosemount Corporation    [XEROX]
 32981   80D5        -      -     IBM SNA Service on Ether [XEROX]
 32989   80DD        -      -     Varian Associates        [XEROX]
 32990   80DE-80DF   -      -     Integrated Solutions TRFS[XEROX]
 32992   80E0-80E3   -      -     Allen-Bradley            [XEROX]
 32996   80E4-80F0   -      -     Datability               [XEROX]
 33010   80F2        -      -     Retix                    [XEROX]
 33011   80F3        -      -     AppleTalk AARP (Kinetics)[XEROX]
 33012   80F4-80F5   -      -     Kinetics                 [XEROX]
 33015   80F7        -      -     Apollo Computer          [XEROX]
 33023   80FF        -      -     Wellfleet Communications [XEROX]
 33024   8100        -      -     IEEE 802.1Q VLAN-tagged frames (initially Wellfleet)
 33025   8101-8103   -      -     Wellfleet Communications [XEROX]
 33031   8107-8109   -      -     Symbolics Private        [XEROX]
 33072   8130        -      -     Hayes Microcomputers     [XEROX]
 33073   8131        -      -     VG Laboratory Systems    [XEROX]
 33074   8132-8136                Bridge Communications    [XEROX]
 33079   8137-8138   -      -     Novell, Inc.             [XEROX]
 33081   8139-813D   -      -     KTI                      [XEROX]
         8148                     Logicraft                [XEROX]
         8149                     Network Computing Devices[XEROX]
         814A                     Alpha Micro              [XEROX]
 33100   814C        -      -     SNMP                      [JKR1]
         814D                     BIIN                     [XEROX]
         814E                     BIIN                     [XEROX]
         814F                     Technically Elite Concept[XEROX]
         8150                     Rational Corp            [XEROX]
         8151-8153                Qualcomm                 [XEROX]
         815C-815E                Computer Protocol Pty Ltd[XEROX]
         8164-8166                Charles River Data System[XEROX]
	 817D			  XTP			   [XEROX]
	 817E	                  SGI/Time Warner prop.    [XEROX]
	 8180	                  HIPPI-FP encapsulation   [XEROX]
	 8181	                  STP, HIPPI-ST            [XEROX]
	 8182	                  Reserved for HIPPI-6400  [XEROX]
	 8183	                  Reserved for HIPPI-6400  [XEROX]
	 8184-818C                Silicon Graphics prop.   [XEROX]
         818D                     Motorola Computer        [XEROX]
         819A-81A3                Qualcomm                 [XEROX]
         81A4                     ARAI Bunkichi            [XEROX]
         81A5-81AE                RAD Network Devices      [XEROX]
         81B7-81B9                Xyplex                   [XEROX]
         81CC-81D5                Apricot Computers        [XEROX]
         81D6-81DD                Artisoft                 [XEROX]
         81E6-81EF                Polygon                  [XEROX]
         81F0-81F2                Comsat Labs              [XEROX]
         81F3-81F5                SAIC                     [XEROX]
         81F6-81F8                VG Analytical            [XEROX]
         8203-8205                Quantum Software         [XEROX]
         8221-8222                Ascom Banking Systems    [XEROX]
         823E-8240                Advanced Encryption Syste[XEROX]
         827F-8282                Athena Programming       [XEROX]
         8263-826A                Charles River Data System[XEROX]
         829A-829B                Inst Ind Info Tech       [XEROX]
         829C-82AB                Taurus Controls          [XEROX]
         82AC-8693                Walker Richer & Quinn    [XEROX]
         8694-869D                Idea Courier             [XEROX]
         869E-86A1                Computer Network Tech    [XEROX]
         86A3-86AC                Gateway Communications   [XEROX]
         86DB                     SECTRA                   [XEROX]
         86DE                     Delta Controls           [XEROX]
         86DD                     IPv6                      [IANA]
 34543   86DF        -      -     ATOMIC                  [Postel]
         86E0-86EF                Landis & Gyr Powers      [XEROX]
         8700-8710                Motorola                 [XEROX]
 34667   876B        -      -     TCP/IP Compression     [RFC1144]
 34668   876C        -      -     IP Autonomous Systems  [RFC1701]
 34669   876D        -      -     Secure Data            [RFC1701]
         880B                     PPP                       [IANA] 
         8847                     MPLS                      [RFC5332]
         8848                     MPLS with upstream-assigned label  [RFC5332]
         8A96-8A97                Invisible Software       [XEROX]
 34915   8863        -      -     PPPoE Discovery Stage  [RFC2516]
 34916   8864        -      -     PPPoE Session Stage    [RFC2516]
 36864   9000        -      -     Loopback                 [XEROX]
 36865   9001        -      -     3Com(Bridge) XNS Sys Mgmt[XEROX]
 36866   9002        -      -     3Com(Bridge) TCP-IP Sys  [XEROX]
 36867   9003        -      -     3Com(Bridge) loop detect [XEROX]
 65280	 FF00        -      -     BBN VITAL-LanBridge cache[XEROX] 
         FF00-FF0F                ISC Bunker Ramo          [XEROX]
 65535   FFFF        -      -     Reserved               [RFC1701]

The standard for transmission of IP datagrams over Ethernets and
Experimental Ethernets is specified in [RFC894] and [RFC895]
respectively.

NOTE:  Ethernet 48-bit address blocks are assigned by the IEEE.

IEEE Registration Authority
c/o Iris Ringel
IEEE Standards Department
445 Hoes Lane, P.O. Box 1331
Piscataway, NJ 08855-1331
Phone +1 732 562 3813
Fax: +1 732 562 1571
Email: <i.ringel&ieee.org>


ETHERNET VENDOR ADDRESS COMPONENTS or ORGANIZATIONALLY UNIQUE IDENTIFIERS

Ethernet hardware addresses are 48 bits, expressed as 12 hexadecimal
digits (0-9, plus A-F, capitalized).  These 12 hex digits consist of
the first/left 6 digits (which should match the vendor of the Ethernet
interface within the station) and the last/right 6 digits which
specify the interface serial number for that interface vendor.

These high-order 3 octets (6 hex digits) are also known as the
Organizationally Unique Identifier or OUI.

Ethernet addresses might be written unhyphenated (e.g., 123456789ABC),
or with one hyphen (e.g., 123456-789ABC), but should be written
hyphenated by octets (e.g., 12-34-56-78-9A-BC).

These addresses are physical station addresses, not multicast nor
broadcast, so the second hex digit (reading from the left) will be
even, not odd.

At present, it is not clear how the IEEE assigns Ethernet block
addresses.  Whether in blocks of 2**24 or 2**25, and whether
multicasts are assigned with that block or separately.  A portion of
the vendor block address is reportedly assigned serially, with the
other portion intentionally assigned randomly.  If there is a global
algorithm for which addresses are designated to be physical (in a
chipset) versus logical (assigned in software), or globally-assigned
versus locally-assigned addresses, some of the known addresses do not
follow the scheme (e.g., AA0003; 02xxxx).

Another list of Ethernet vendor address components is maitained by
Michael A. Patton and is accessible at:

    <URL:http://www.cavebear.com/CaveBear/Ethernet/vendor.html>
    <URL:ftp://ftp.cavebear.com/pub/Ethernet-codes>
    <URL:gopher://ftp.cavebear.com/00/pub/Ethernet-codes>

00000C  Cisco
00000E  Fujitsu
00000F  NeXT
000010  Sytek
00001D  Cabletron
000020  DIAB (Data Intdustrier AB)
000022  Visual Technology
00002A  TRW
000032  GPT Limited (reassigned from GEC Computers Ltd)
00005A  S & Koch
00005E  IANA
000065  Network General
00006B  MIPS
000077  Interphase Corporation
00007A  Ardent
000080  Cray Communications A/S
000089  Cayman Systems  Gatorbox
000093  Proteon
00009F  Ameristar Technology
0000A2  Wellfleet
0000A3  Network Application Technology
0000A6  Network General (internal assignment, not for products)
0000A7  NCD             X-terminals
0000A9  Network Systems
0000AA  Xerox           Xerox machines
0000B3  CIMLinc
0000B7  Dove            Fastnet
0000BC  Allen-Bradley
0000C0  Western Digital
0000C5  Farallon phone net card
0000C6  HP Intelligent Networks Operation (formerly Eon Systems)
0000C8  Altos
0000C9  Emulex          Terminal Servers
0000D0  Develcon
0000D7  Dartmouth College (NED Router)
0000D8  3Com? Novell?   PS/2
0000DD  Gould
0000DE  Unigraph
0000E2  Acer Counterpoint
0000EF  Alantec
0000FD  High Level Hardvare (Orion, UK)
000102  BBN             BBN internal usage (not registered)
0010D1  BlazeNet
001700  Kabel
0020AF  3COM ???
0020C9  Victron
002094  Cubix
008064  Wyse Technology / Link Technologies
00802B  IMAC ???
00802D  Xylogics, Inc.  Annex terminal servers
00808C  Frontier Software Development
0080C2  IEEE 802.1 Committee
0080D3  Shiva
00A03E  ATM Forum
00AA00  Intel
00DD00  Ungermann-Bass
00DD01  Ungermann-Bass
020701  Racal InterLan
020406  BBN             BBN internal usage (not registered)
026086  Satelcom MegaPac (UK)
02608C  3Com            IBM PC; Imagen; Valid; Cisco
02CF1F  CMC             Masscomp; Silicon Graphics; Prime EXL
080002  3Com (Formerly Bridge)
080003  ACC (Advanced Computer Communications)
080005  Symbolics       Symbolics LISP machines
080008  BBN
080009  Hewlett-Packard
08000A  Nestar Systems
08000B  Unisys
080011  Tektronix, Inc.
080014  Excelan         BBN Butterfly, Masscomp, Silicon Graphics
080017  NSC
08001A  Data General
08001B  Data General
08001E  Apollo
080020  Sun             Sun machines
080022  NBI
080025  CDC
080026  Norsk Data (Nord)
080027  PCS Computer Systems GmbH
080028  TI              Explorer
08002B  DEC
08002E  Metaphor
08002F  Prime Computer  Prime 50-Series LHC300
080036  Intergraph      CAE stations
080037  Fuji-Xerox
080038  Bull
080039  Spider Systems
080041  DCA Digital Comm. Assoc.
080045  ???? (maybe Xylogics, but they claim not to know this number)
080046  Sony
080047  Sequent
080049  Univation
08004C  Encore
08004E  BICC
080056  Stanford University
080058  ???             DECsystem-20
08005A  IBM
080067  Comdesign
080068  Ridge
080069  Silicon Graphics
08006E  Concurrent      Masscomp
080075  DDE (Danish Data Elektronik A/S)
08007C  Vitalink        TransLAN III
080080  XIOS
080086  Imagen/QMS
080087  Xyplex          terminal servers
080089  Kinetics        AppleTalk-Ethernet interface
08008B  Pyramid
08008D  XyVision        XyVision machines
080090  Retix Inc       Bridges
484453  HDS ???
800010  AT&T            
AA0000  DEC             obsolete
AA0001  DEC             obsolete
AA0002  DEC             obsolete
AA0003  DEC             Global physical address for some DEC machines
AA0004  DEC             Local logical address for systems running 
                        DECNET
The CFxxxx Series

RFC 2153 describes a method of usings a "pseudo OUI" for certain
purposes when there is no appropriate regular OUI assigned.  These are
listed here.

CF0001  Data Comm for Business                                  [McCain]

ETHERNET MULTICAST ADDRESSES

An Ethernet multicast address consists of the multicast bit, the
23-bit vendor component, and the 24-bit group identifier assigned by
the vendor.  For example, DEC is assigned the vendor component
08-00-2B, so multicast addresses assigned by DEC have the first
24-bits 09-00-2B (since the multicast bit is the low-order bit of the
first byte, which is "the first bit on the wire").

Another list of Ethernet multicast addresses is maintained by Michael
A. Patton and is accessible at:

    <URL:http://www.cavebear.com/CaveBear/ether-codes.html>
    <URL:ftp://ftp.cavebear.com/pub/Ethernet-codes>
    <URL:gopher://ftp.cavebear.com/00/pub/Ethernet-codes>

Ethernet                Type
Address                 Field   Usage

Multicast Addresses:

01-00-5E-00-00-00-      0800    Internet Multicast        [RFC1112]
01-00-5E-7F-FF-FF
01-00-5E-80-00-00-      8847/8848  MPLS Multicast         [RFC5332]
01-00-5E-8F-FF-FF
01-00-5E-90-00-00-      ????    Internet reserved by IANA
01-00-5E-FF-FF-FF
01-80-C2-00-00-00       -802-   Spanning tree (for bridges)
09-00-02-04-00-01?      8080?   Vitalink printer
09-00-02-04-00-02?      8080?   Vitalink management
09-00-09-00-00-01       8005    HP Probe
09-00-09-00-00-01       -802-   HP Probe
09-00-09-00-00-04       8005?   HP DTC
09-00-1E-00-00-00       8019?   Apollo DOMAIN
09-00-2B-00-00-00       6009?   DEC MUMPS?
09-00-2B-00-00-01       8039?   DEC DSM/DTP?
09-00-2B-00-00-02       803B?   DEC VAXELN?
09-00-2B-00-00-03       8038    DEC Lanbridge Traffic Monitor (LTM)
09-00-2B-00-00-04       ????    DEC MAP End System Hello
09-00-2B-00-00-05       ????    DEC MAP Intermediate System Hello
09-00-2B-00-00-06       803D?   DEC CSMA/CD Encryption?
09-00-2B-00-00-07       8040?   DEC NetBios Emulator?
09-00-2B-00-00-0F       6004    DEC Local Area Transport (LAT)
09-00-2B-00-00-1x       ????    DEC Experimental
09-00-2B-01-00-00       8038    DEC LanBridge Copy packets 
                                (All bridges)
09-00-2B-01-00-01       8038    DEC LanBridge Hello packets 
                                (All local bridges)
                                1 packet per second, sent by the
                                designated LanBridge
09-00-2B-02-00-00       ????    DEC DNA Lev. 2 Routing Layer routers?
09-00-2B-02-01-00       803C?   DEC DNA Naming Service Advertisement?
09-00-2B-02-01-01       803C?   DEC DNA Naming Service Solicitation?
09-00-2B-02-01-02       803E?   DEC DNA Time Service?
09-00-2B-03-xx-xx       ????    DEC default filtering by bridges?
09-00-2B-04-00-00       8041?   DEC Local Area Sys. Transport (LAST)?
09-00-2B-23-00-00       803A?   DEC Argonaut Console?
09-00-4E-00-00-02?      8137?   Novell IPX
09-00-56-00-00-00-      ????    Stanford reserved
09-00-56-FE-FF-FF
09-00-56-FF-00-00-      805C    Stanford V Kernel, version 6.0
09-00-56-FF-FF-FF
09-00-77-00-00-01       ????    Retix spanning tree bridges
09-00-7C-02-00-05       8080?   Vitalink diagnostics
09-00-7C-05-00-01       8080?   Vitalink gateway?
0D-1E-15-BA-DD-06       ????    HP
AB-00-00-01-00-00       6001    DEC Maintenance Operation Protocol 
                                (MOP) Dump/Load Assistance
AB-00-00-02-00-00       6002    DEC Maintenance Operation Protocol 
                                (MOP) Remote Console
                                1 System ID packet every 8-10 minutes,
                                by every:
                                DEC LanBridge
                                DEC DEUNA interface
                                DEC DELUA interface
                                DEC DEQNA interface
                                (in a certain mode)
AB-00-00-03-00-00       6003    DECNET Phase IV end node Hello 
                                packets 1 packet every 15 seconds, 
                                sent by each DECNET host
AB-00-00-04-00-00       6003    DECNET Phase IV Router Hello packets
                                1 packet every 15 seconds, sent by 
                                the DECNET router
AB-00-00-05-00-00       ????    Reserved DEC through
AB-00-03-FF-FF-FF
AB-00-03-00-00-00       6004    DEC Local Area Transport (LAT) - old
AB-00-04-00-xx-xx       ????    Reserved DEC customer private use
AB-00-04-01-xx-yy       6007    DEC Local Area VAX Cluster groups
                                Sys. Communication Architecture (SCA)
CF-00-00-00-00-00       9000    Ethernet Configuration Test protocol 
                                (Loopback)

Broadcast Address:

FF-FF-FF-FF-FF-FF       0600    XNS packets, Hello or gateway search?
                                6 packets every 15 seconds, per XNS 
                                station
FF-FF-FF-FF-FF-FF       0800    IP (e.g. RWHOD via UDP) as needed
FF-FF-FF-FF-FF-FF       0804    CHAOS
FF-FF-FF-FF-FF-FF       0806    ARP (for IP and CHAOS) as needed
FF-FF-FF-FF-FF-FF       0BAD    Banyan
FF-FF-FF-FF-FF-FF       1600    VALID packets, Hello or gateway 
                                search?
                                1 packets every 30 seconds, per VALID 
                                station
FF-FF-FF-FF-FF-FF       8035    Reverse ARP
FF-FF-FF-FF-FF-FF       807C    Merit Internodal (INP)
FF-FF-FF-FF-FF-FF       809B    EtherTalk



IANA ETHERNET ADDRESS BLOCK - UNICAST USE

The IANA owns an Ethernet address block which may be used for
unicast address assignments or other special purposes.

The IANA may assign unicast global IEEE 802 MAC address from it's
assigned OUI (00-00-5E) for use in IETF standard track protocols.  The
intended usage is for dynamic mapping between IP addresses and IEEE
802 MAC addresses.  These IEEE 802 MAC addresses are not to be
permanently assigned to any hardware interface, nor is this a
substitute for a network equipment supplier getting its own OUI.

The address block in IEEE binary is:  0000 0000 0000 0000 0111 1010

In the normal Internet dotted decimal notation this is 0.0.94 since
the bytes are transmitted higher order first and bits within bytes are
transmitted lower order first.

IEEE CSMA/CD and Token Bus bit transmission order: 00 00 5E

IEEE Token Ring bit transmission order: 00 00 7A

Appearance on the wire (bits transmitted from left to right):

    0                           23                            47
    |                           |                             |
    0000 0000 0000 0000 0111 1010 xxxx xxxx xxxx xxxx xxxx xxxx
    |
    Multicast Bit

Appearance in memory (bits transmitted right-to-left within octets,
octets transmitted left-to-right):

    0                           23                            47
    |                           |                             |
    0000 0000 0000 0000 0101 1110 xxxx xxxx xxxx xxxx xxxx xxxx
            |
            Multicast Bit

The latter representation corresponds to the Internet standard
bit-order, and is the format that most programmers have to deal with.
Using this representation, the range of Internet Unicast addresses is:

       00-00-5E-00-00-00  to  00-00-5E-FF-FF-FF  in hex, or

       0.0.94.0.0.0  to  0.0.94.255.255.255  in dotted decimal

The low order 24 bits of these unicast addresses are assigned as
follows:

Dotted Decimal          Description			Reference
----------------------- ------------------------------- ---------
000.000.000-000.000.255 Reserved			[IANA]
000.001.000-000.001.255 Virtual Router Redundancy (VRRP)	[RFC3768]



IANA ETHERNET ADDRESS BLOCK - MULTICAST USE

The IANA owns an Ethernet address block which may be used for
multicast address asignments or other special purposes.

The address block in IEEE binary is:  0000 0000 0000 0000 0111 1010

In the normal Internet dotted decimal notation this is 0.0.94 since
the bytes are transmitted higher order first and bits within bytes are
transmitted lower order first.

IEEE CSMA/CD and Token Bus bit transmission order: 00 00 5E

IEEE Token Ring bit transmission order: 00 00 7A

Appearance on the wire (bits transmitted from left to right):

    0                           23                            47
    |                           |                             |
    1000 0000 0000 0000 0111 1010 xxxx xxx0 xxxx xxxx xxxx xxxx
    |                                     |
    Multicast Bit                         0 = Internet Multicast
                                          1 = Assigned by IANA for
                                              other uses

Appearance in memory (bits transmitted right-to-left within octets,
octets transmitted left-to-right):

    0                           23                            47
    |                           |                             |
    0000 0001 0000 0000 0101 1110 0xxx xxxx xxxx xxxx xxxx xxxx
            |                     |
            Multicast Bit         0 = Internet Multicast
                                  1 = Assigned by IANA for other uses

The latter representation corresponds to the Internet standard
bit-order, and is the format that most programmers have to deal with.
Using this representation, the range of Internet Multicast addresses
is:

       01-00-5E-00-00-00  to  01-00-5E-7F-FF-FF  in hex, or

       1.0.94.0.0.0  to  1.0.94.127.255.255  in dotted decimal


Modified EUI-64 Addresses in the IANA Ethernet Address Block - per [RFC5214]

Modified EUI-64 addresses ([RFC4291], Appendix A) in the IANA Ethernet 
Address Block are formed by concatenating the 24-bit IANA OUI (00-00-5E) 
with a 40-bit extension identifier and inverting the "u" bit, i.e., the 
"u" bit is set to one (1) to indicate universal scope and it is set to 
zero (0) to indicate local scope.

Modified EUI-64 addresses have the following appearance in memory
(bits transmitted right-to-left within octets, octets transmitted
left-to-right):

   0                       23                                        63
   |        OUI            |            extension identifier         |
   000000ug00000000 01011110xxxxxxxx xxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxx

   When the first two octets of the extension identifier encode the
   hexadecimal value 0xFFFE, the remainder of the extension identifier
   encodes a 24-bit vendor-supplied id as follows:

   0                       23               39                       63
   |        OUI            |     0xFFFE     |   vendor-supplied id   |
   000000ug00000000 0101111011111111 11111110xxxxxxxx xxxxxxxxxxxxxxxx

   When the first octet of the extension identifier encodes the
   hexadecimal value 0xFE, the remainder of the extension identifier
   encodes a 32-bit IPv4 address as follows:

   0                       23      31                                63
   |        OUI            |  0xFE |           IPv4 address          |
   000000ug00000000 0101111011111110 xxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxx



SNAP PROTOCOL IDS IN THE IANA ETHERNET ADDRESS BLOCK

The Sub-Network Access Protocol (SNAP) header contains 40 bits: 24
bits containing an IEEE-assigned Organizationally Unique Identifier
(OUI), and 16 bits containing a Protocol Identifier (PID).  The OUIs
are the same as those used in the Ethernet Vendor Address Components
list above.  The IANA's OUI, 00-00-5E, may be used in SNAP headers
with the appropriate PID to identify the protocols listed below.

Note that the IANA restricts this list to protocols that are ONLY
identified in this manner; if a protocol has an EtherType, then SNAP
headers identifying that protocol must contain an OUI of 00-00-00,
with the EtherType in the PID field.

The SNAP PID assignments using the IANA's OUI are:

Protocol ID      Description				References
-----------      -----------				----------
decimal  Hex      
  0001   0001    MARS Data Messages (short form)	[RFC2022]
  0002   0002    reserved for future NHRP use		[RFC2332]
  0003   0003    MARS/NHRP Control Messages		[RFC2022, 2332]
  0004   0004    MARS Data Messages (long form)		[RFC2022]
  0005   0005    SCSP - Server Cache Sync Protocol      [RFC2334]
  0006   0006    VRID - Virtual Router MAC Address      [Knight]
  0007   0007    L2TP                                   [RFC3070]
  0008   0008    Virtual Private Network ID             [Malis-ID]
  0009   0009    MSDP-GRE-Protocol Type                 [msdp-ID]


References
----------
[RFC894]   Hornig, C., "A Standard for the Transmission of IP Datagrams
           over Ethernet Networks, STD 41, RFC 894, Symbolics, 
           April 1984.

[RFC895]   Postel, J., "A Standard for the Transmission of IP Datagrams
           over Experimental Ethernet Networks, STD 42, RFC 895, 
           USC/Information Sciences Institute, April 1984.

[RFC1112]  Deeering, S., "Host Extensions for IP Multicasting", 
           STD 5, RFC 1112, Stanford University, August 1989.

[RFC1701]  Hanks, S., Li, T, Farinacci, D., and P. Traina,
           "Generic Routing Encapsulation", RFC 1701, NetSmiths, Ltd.,
           and cisco Systems, October 1994.

[RFC2022]  Armitage, G., "Support for Multicast over UNI 3.0/3.1 based
           ATM Networks", RFC 2022, Bellcore, November 1996.

[RFC2332]  Luciani, J., et al, "NBMA Next Hop Resolution Protocol
           (NHRP)", RFC 2332, April 1998.

[RFC2334]  Luciani, J., et al, "Server Cache Synchronization Protocol
           (SCSP)", RFC 2334, April 1998.

[RFC2516]  Mamakos, L., et al, "A Method for Transmitting PPP Over
           Ethernet (PPPoE)", RFC 2516, February 1999.

[RFC3070]  Rawat, V., R. Tio, S. Nanji, and R. Verma, "Layer Two
           Tunneling Protocol (L2TP) over Frame Relay", RFC 3070,
           February 2001.

[RFC3768]  R. Hinden, Ed., "Virtual Router Redundancy Protocol (VRRP)",
           RFC 3768, April 2004.
           
[RFC4291]  R. Hinden, S. Deering, "IP Version 6 Addressing Architecture",
           RFC 4291, February 2006.

[RFC5214]  F. Templin, T. Gleeson, D. Thaler, "Intra-Site Automatic 
           Tunnel Addressing Protocol (ISATAP)", RFC 5214, March 2008.

[RFC5332]  T. Eckert, E. Rosen, Ed., R. Aggarwal, Y. Rekhter, "MPLS 
           Multicast Encapsulations", RFC 5332, August 2008.

[RFC-eastlake-ethernet-iana-considerations-08.txt]
           D. Eastlake, "IANA Considerations and IETF Protocol Usage for 
           IEEE 802 Parameters", RFC XXXX, Month Year.

People
------
[AXC] Andrew Cherenson <arc&SGI.COM>

[Hinden] Bon Hinden, <hinden&ipsilon.com>, January 1998.

[HWB] Hans-Werner Braun <HWB&MCR.UMICH.EDU>

[IANA] Internet Assigned Numbers Authority, <iana&iana.org>, October 1996.

[JXM] Joseph Murdock <---none--->

[Knight] S. Knight, <steven.knight&ascend.com>, November 1997.

[Malis] Andy Malis, <malis&ascend.com>, October 1996.

[Malis-ID] <draft-ietf-ion-multiprotocol-atm-02.txt>, April 1999.

[McCain] John McCain, <jmccain&dcbnet.com>, July 1997.

[msdp-ID] <draft-ietf-msdp-spec-09.txt>, May 2001.

[DCP1] David Plummer <DCP&SCRC-QUABBIN.ARPA>

[Postel] Jon Postel <postel&isi.edu>

[JKR1] Joyce K. Reynolds <jkrey&isi.edu>

[Verma] Rohit Verma <Rohit_Verma&mw.3com.com>, August 1998.

[XEROX] Neil Sembower <sembower&eso.mc.xerox.com>

[DT15] Daniel Tappan <Tappan&BBN.COM>

[]

1.6. 참고자료

OSI 7 계층모델
TCP(Transmission Control Protocol)
Ethernet frame(https://en.wikipedia.org/wiki/Ethernet_frame)
https://en.wikipedia.org/wiki/Address_Resolution_Protocol
https://en.wikipedia.org/wiki/Reverse_Address_Resolution_Protocol
IEEE 802 Numbers (ETHER TYPES, ORGANIZATIONALLY UNIQUE IDENTIFIERS, Logical Link Control (LLC) Numbers)(https://www.iana.org/assignments/ieee-802-numbers/ieee-802-numbers.xhtml)
- http://standards-oui.ieee.org/ethertype/eth.txt
RFC826 - An Ethernet Address Resolution Protocol or Converting Network Protocol Addresses to 48.bit Ethernet Address for Transmission on Ethernet Hardware(https://tools.ietf.org/html/rfc826)
RFC903 - A Reverse Address Resolution Protocol(https://tools.ietf.org/html/rfc903)
RFC2390 - Inverse Address Resolution Protocol(https://tools.ietf.org/html/rfc2390)
RFC5227 - IPv4 Address Conflict Detection(https://tools.ietf.org/html/rfc5227)
RFC7042 - IANA Considerations and IETF Protocol and Documentation Usage for IEEE 802 Parameters(https://tools.ietf.org/html/rfc7042)
802.1Q, 802.1q, IEEE 802.1Q Institute of Electrical and Electronic Engineers 802.1q - 정보통신기술용어해설(http://www.ktword.co.kr/test/view/view.php?m_temp1=2136)
https://en.wikipedia.org/wiki/IEEE_802.1Q
https://en.wikipedia.org/wiki/IEEE_P802.1p
https://en.wikipedia.org/wiki/IEEE_802.1ad
http://www.ieee802.org/1/pages/802.1Q-2014.html

값	종류
06H	IP
42H	BPDU
7EH	X.25 PLP
80H	XNS
E0H	Netware IPX
F0H	NetBIOS
FFH	Global SAP
AAH	IEEE SNAP

값	설명
1	ARP Request
2	ARP Reply
3	RARP Request
4	RARP Reply