P = lim (n /nå), nå ¥ |
n - ;
nå - , .
- :
P = lim (n /nå), nå ¥ |
. ( . IPLR) - :
P = lim (n /nå), nå ¥ |
n - ;
nå - .
P = lim (n /nå), t ¥ |
n - , ;
nå - , t.
- , .
ó
- () . , , : , , .
t , (, ) :
M N t = t + åtp,i + å (t,j) +t,j, i=1 j=1 |
M ;
N ;
t ( ( ), );
t p,i i- ;
t ,j j- ;
t ,j j- .
, . - , - . , . , , .
|
|
( ) , .
, | ||||
10-7 | 10-3 | 10-3 | 25/500 | |
10-7 | 10-6 | 10-6 | 50/1000 | |
10-5 | 10-3 | 10-3 | 1000 | |
10-5 | 10-7 | 10-7 | 1000 | |
10-6 | 10 -8 | 10 -8 | 1000 |
, 25 - G.164. , 150 .
9.1, . .
20- - 50 , .
MPLS
MPLS (Multiprotocol Label Switching) , TCP/IP, , IPX/SPX. MPLS () () , ATM, Frame Relay, X.25, IEEE 802.3 . ().
MPLS
IP- () ( IP-) , . (Provider router) . IP- MPLS- IP-, IP-, . ( QoS, Quality of Service ) , .
MPLS ( 4 ) :
- (20 ) ;
|
|
- (CoS, Class of Service), CoS 3 , , QoS;
- S (1 );
- (TTL, Time To Live). , 8 , IP- , , MPLS, IP.
MPLS , (Point-Point Protocol , ) Ethernet ().
PPP Ethernet MPLS
, MPLS - , Ethernet. , MPLS , IP-.
Ethernet MPLS 3- (L3, IP).
MPLS- MPLS LSP (Label Switching Path ), , MPLS . , MPLS Ethernet, - Ethernet, .
( MPLS) . LSP.
, TCP/IP ().
MPLS
MPLS :
- IP- ( CE);
- MPLS ( P PE ).
, . , VPN. ; IP- , , , . , PE , . :
- ( );
- VPN (VPN Routing and Forwarding instance, VRF) , (). , .
1.9 VRF, A (VRF ), (VRF ).
VRF IGP (Interior Gateway Protocols ). IGP , , , . . , , VRF , VPN BGP. (Border Gateway Protocol ). BGP TCP. BGP, , , , , , ( VPN). BGP , . , VRF.
|
|
, VPN.
, MPLS . MPLS IP-. , IP, VPN, RD (Route Distinguisher ), VPN. , VPN, , IP. .
MPLS , MPLS QoS.
MPLS :
- MPLS , , IP-.
- MPLS (ATM, Frame Relay, X.25, IEEE 802.3 ).
- MPLS . .
- MPLS (QoS). , , , .
- MPLS , IP- , WAN, IP- .
MPLS IP, , VPN , . MPLS , IPSec , .