SNMP PDU, PDU Get, GetNext, Set, Response , Trap (. . 9).
, PDU Get, GetNext, Set, Response:
PDU. , . (.. ). 0 232-1. Get, GetNext SET Response, .
. ( ), .
. , (error index) , . error index badvalue, readonly nosuchname.
2.
Noerror | ; | |
Toobig | ; | |
Nosuchname | ; | |
badvalue | set ; | |
Readonly | ; | |
Generr | . |
, SNMP, , , .
SNMP, , . ITU-T .209 (BER Basic Encoding Rules ). 2.3 .
, , , , 0, T-L-V (Tag-Length-Value).
, SNMP, ASN.1, (), SNMP, (BER), . SNMP - (class tag=10) (constructor).
Trap, PDU:
SNMP | PDU ( Trap) | ( MIB, ) | ||||||||||||||||||||
(Community) | PDU | (Enterprise) | Trap | . | (Tag) | (L) | (Value) | |||||||||||||||
Vers 1 | : public | . .1 | OID | Network Address (IP-Address) | . .3 | INTEGER | TimeTicks | *** | **** | (Tag) | (L) | |||||||||||
T | L | V | T | L | V | T | L | V | T | L | V | T | L | V | T | L | T | L | V | |||
9 PDU-SNMP-Trap
|
|
PDU-Trap:
(enterprise) ;
, , IP-;
(Trap) , (. 2):
3 TRAP
TRAP | TRAP | |
Coldstart | . | |
Warmstart | . | |
Linkdown | . . | |
Linkup | . . | |
Authenticationfailure | SNMP- (community). | |
EGPneighborloss | EGP- . IP- . | |
Entrprisespecific | TRAP . |
TRAP 04 .
( ) . coldstart 200 .
2.3 SNMP
2.3.1 () ASN.1
, (), (), .. .
, , (), , .. .
() , , .
, :
;
( ) ;
ASN.1 (X.208), BER (Basic Encoding Rules - X.209).
ASN.1 OSI, , CMIP, OMAP SNMP, MIB, (, FTP, MAP, INAP ..).
|
|
ASN.1 , , , , .
, . , , , , ASN.1, . MIB, ASN.1, , .
ASN.1 , , ++.
ASN.1 , , . ., , , .
ASN.1 , . ( ) , . , - .
ASN.1 :
A Z |
a z |
0 t 9 |
: =, { } <. |
() [ ] - ' |
ASN.1 ( )
BOOLEAN | OPTIONAL | INCLUDES |
INTEGER | DEFAULT | MIN |
BIT | COMPONENTS | MAX |
STRING | UNIVERSAL | SIZE |
OCTET | APPLICATION | FROM |
NULL | PRIVATE | WITH |
SEQUENCE | TRUE | COMPONENT |
OF | FALSE | PRESENT |
SET | BEGIN | ABSENT |
IMPLICIT | END | DEFINED |
CHOICE | DEFINITIONS | BY |
ANY | EXPLICIT | PLUS-INFINITY |
EXTERNAL | ENUMERATED | MINUS-INFINITY |
OBJECT | EXPORTS | TAGS |
IDENTIFIER | IMPORTS |
, ASN.1, , C++. , , .
ASN.1 (). , .
ASN.1 :
(-) () ;
() (-) , . , , , , , (, MIB). , MIT.
ASN.1 , :
SEQUENCE | . |
SET | . |
CHOICE | |
SEQUENCE OF |
ASN.1 , (. TAG, , , , ).
ASN.1 4 ().
1 (UNIVERSAL - UNI) ASN.1 (X.208) , .
2 ( APPLICATION-WIDE APP-W) , (, . .500 ).
3 - (CONTEXT-SPECIFIC C-SPEC) , .
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4 ( PRIVATE - PRIV) , , ISO .
2.3.2 BER
ASN.1 () . (BER . . ITU-T .209).
( T-L-V = Tag-Length-Value):
1. () - , , .
2. - .
3. () (Value, Content) .. .
T | L | V |
() |
, , 0, , , , .
.
2.3.2.1 ().
Tag 8- (. .2-1), 2 (7- 8-), (. .10).
(Content) |
10
4 (7- 8- )
8 | 7 | ||
UNI | |||
APP | |||
- | C-SP | ||
PRIV |
6- . :
(p - primitive) 6- 0,
(c - constructor) 6- 1.
, :
T L - (T L - (T L (V)))
:
(Sequence),
(Set),
() (Choice).
5 () . 5 30 (11110Bin). 5 1, , .
(UNI) 30 , . ITU-T .208 (. . 5).
5 UNI
( 8 7) | p/c ( 6) | ( 54321) | Tag hex | |
UNI (00) | 00001Bin 1Dec | Boolean type | ||
UNI (00) | 00010Bin 2Dec | Integer type | ||
UNI (00) | 00011Bin 3Dec | Bitstring type | ||
UNI (00) | 00100Bin 4Dec | Octetstring type | ||
UNI (00) | 00101Bin 5Dec | Null type | ||
UNI (00) | 00110Bin 6Dec | Object identifier type | ||
UNI (00) | 7Dec | Object descriptor type | ||
UNI (00) | 8Dec | External type | ||
UNI (00) | 9Dec | Real type | ||
UNI (00) | 10Dec | Enumerated type | 0a | |
UNI (00) | 1215Dec | Reserved for future versions | ||
UNI (00) | 16Dec | Sequence and Sequence-of types | ||
UNI (00) | Set and Set-of types | |||
UNI (00) | 0/1 | 1822 2527 | Character string types (, IA5) | 12/32 |
UNI (00) | 23, 24 | Time types | 17, 18 | |
UNI (00) | 28 | Reserved for future versions |
, .
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, . ITU-T Q.773 (00), (01) TCAP. , , (01) . .6.
6 01 (Q.773 ITU-T)
\ | |||||||||
hex | |||||||||
61hex | Unidirectional | ||||||||
62hex | Begin | ||||||||
63hex | (reserved) | ||||||||
64hex | End | ||||||||
65hex | Continue | ||||||||
66hex | (reserved) | ||||||||
67hex | Abort |
. ITU-T X.219, X.229 ROSE . () - (C-SP 10).
. 7
7 ROSE, TCAP.
\ | |||||||||
hex | |||||||||
a1hex | Invoke | ||||||||
a2hex | Return Result (Last) | ||||||||
a3hex | Return Error | ||||||||
a4hex | Reject | ||||||||
a5hex | (reserved) | ||||||||
a6hex | (reserved) | ||||||||
a7hex | Return Result (Not Last) |
(- 10) (, PDU) SNMP ( IETF RFC-1155) . .8.
8 PDU SNMP.
\ | |||||||||
hex | (PDU) | ||||||||
a0hex | GET-request | ||||||||
a1hex | GET_next_request | ||||||||
a2hex | GET response | ||||||||
a3hex | SET-request | ||||||||
a4hex | TRAP |
2.3.2.2
:
1. (. .11). , () 127 . (8-) 0, , ( - LSB), 1- , ( - MSB), 7- .
MSB | LSB | |||||||
( ) |
11
, 38 , , :
L= 00100110Bin (38Dec)
2. (. .12). , () 127 . (8-) 1, , - 1. , , . , ( - LSB), 1- , ( - MSB), 8- .
|
|
MSB | LSB | ||||||
-1 | |||||||
MSB | |||||||
LSB |
12
1: 219 , , :
1- - 10000001Bin (1 )
2- - 11011011Bin (219 )
2: 1347 , , :
1- - 10000010Bin (2 )
2- - 00000101Bin
3- - 01000011Bin (1347 )
:
2- 3-
Hex
100000 10 00000 101 01000011 Bin=1347Dec