BGP.pdf
(
69 KB
)
Pobierz
BGP Ğ P
ART
1
packetlife.net
Attributes
About BGP
Name
Description
Type
Path Vector
Well-known Mandatory Ğ Must be supported and propagated
eBGP AD
20
1 Origin
Origin type (IGP, EGP, or unknown)
iBGP AD
200
List of autonomous systems which the
advertisement has traversed
Standard
RFC 4271
2
AS Path
Protocols
IP
3 Next Hop
External peer in neighboring AS
Transport
TCP/179
Well-known Discretionary Ğ Must be supported; propagation optional
Authentication
MD5
Metric for internal neighbors to reach
external destinations (default 100)
5
Local Preference
Terminology
Includes ASes which have been dropped
due to route aggregation
Autonomous System (AS)
A logical domain under the control of a
single entity
6
Atomic Aggregate
Optional Transitive Ğ Marked as partial if unsupported by neighbor
External BGP (eBGP)
BGP adjacencies which span autonomous
system boundaries
Internal BGP (iBGP)
BGP adjacencies formed within a single AS
Synchronization Requirement
A route must be known by an IGP before
it may be advertised to BGP peers
7
Aggregator
ID and AS of summarizing router
8 Community
Route tag
Optional Nontransitive Ğ Deleted if unsupported by neighbor
Multiple Exit
Discriminator (MED)
Metric for external neighbors to reach the
local AS (default 0)
4
9 Originator ID
The originator of a reflected route
10 Cluster List
List of cluster IDs
Packet Types
13 Cluster ID
Originating cluster
Open
Update
Cisco proprietary, not communicated to
peers (default 0)
--
Weight
Keepalive
Notification
Path Selection
Neighbor States
Attribute
Weight
Description
Preference
Highest
Idle Ğ Neighbor is not responding
1
Administrative preference
Active Ğ Attempting to connect
Communicated between peers
within an AS
Connect Ğ TCP session established
2
Local Preference
Highest
Open Sent Ğ Open message sent
3
Self-originated
Prefer paths originated locally
True
Open Confirm Ğ Response received
4
AS Path
Minimize AS hops
Shortest
Established Ğ Adjacency established
Prefer IGP-learned routes over
EGP, and EGP over unknown
5
Origin
IGP
Troubleshooting
6
MED
Used externally to enter an AS
Lowest
show ip bgp [summary]
7
External
Prefer eBGP routes over iBGP
eBGP
show ip bgp neighbors
8
IGP Cost
Consider IGP metric
Lowest
show ip route [bgp]
9
eBGP Peering
Favor more stable routes
Oldest
clear ip bgp * [soft]
10
Router ID
Tie breaker
Lowest
debug ip bgp [۫]
Influencing Path Selection
Weight
neighbor 172.16.0.1 weight 200
MED
default-metric 400
Local Preference
bgp default local-preference 100
Route Map
neighbor 172.16.0.1 route-map Foo
Ignore
AS Path
bgp bestpath as-path ignore
Ignore Cost
Communities
bgp bestpath cost-community ignore
by Jeremy Stretch
v2.1-r1
BGP Ğ P
ART
2
packetlife.net
Configuration Example
Router A
interface Serial1/0
description Backbone to B
ip address 172.16.0.1 255.255.255.252
AS 65100
F2/0
!
interface Serial1/1
description Backbone to C
ip address 172.16.0.5 255.255.255.252
A
S1/0
S1/1
!
interface FastEthernet2/0
description LAN
ip address 192.168.1.1 255.255.255.0
172.16.0.0/30
172.16.0.4/30
AS 65200
!
router bgp 65100
no synchronization
network 172.16.0.0 mask 255.255.255.252
network 172.16.0.4 mask 255.255.255.252
network 192.168.1.0
neighbor South peer-group
neighbor South remote-as 65200
neighbor 172.16.0.2 peer-group South
neighbor 172.16.0.6 peer-group South
no auto-summary
S1/0
S1/0
F0/0
F0/0
10.0.0.0/30
B
C
F2/0
F2/0
OSPF
Router B
Router C
interface FastEthernet0/0
description Backbone to C
ip address 10.0.0.1 255.255.255.252
interface FastEthernet0/0
description Backbone to B
ip address 10.0.0.2 255.255.255.252
!
interface Serial1/0
description Backbone to A
ip address 172.16.0.2 255.255.255.252
!
interface Serial1/0
description Backbone to A
ip address 172.16.0.6 255.255.255.252
!
interface FastEthernet2/0
description LAN
ip address 192.168.2.1 255.255.255.0
!
interface FastEthernet2/0
description LAN
ip address 192.168.3.1 255.255.255.0
!
router ospf 100
network 10.0.0.1 0.0.0.0 area 0
network 192.168.2.1 0.0.0.0 area 1
!
router ospf 100
network 10.0.0.2 0.0.0.0 area 0
network 192.168.3.1 0.0.0.0 area 2
!
router bgp 65200
no synchronization
redistribute ospf 100 route-map LAN_Subnets
neighbor 10.0.0.2 remote-as 65200
neighbor 172.16.0.1 remote-as 65100
no auto-summary
!
router bgp 65200
no synchronization
redistribute ospf 100 route-map LAN_Subnets
neighbor 10.0.0.1 remote-as 65200
neighbor 172.16.0.5 remote-as 65100
no auto-summary
!
access-list 10 permit 192.168.0.0 0.0.255.255
!
route-map LAN_Subnets permit 10
match ip address 10
set metric 100
!
access-list 10 permit 192.168.0.0 0.0.255.255
!
route-map LAN_Subnets permit 10
match ip address 10
set metric 100
Router A Routing Table
Router B Routing Table
172.16.0.0/30 is subnetted, 2 subnets
C 172.16.0.4 is directly connected, S1/1
C 172.16.0.0 is directly connected, S1/0
C 192.168.1.0/24 is directly connected, F2/0
B 192.168.2.0/24 [20/100] via 172.16.0.2
B 192.168.3.0/24 [20/100] via 172.16.0.2
172.16.0.0/30 is subnetted, 2 subnets
B 172.16.0.4 [20/0] via 172.16.0.1
C 172.16.0.0 is directly connected, S1/0
10.0.0.0/30 is subnetted, 1 subnets
C 10.0.0.0 is directly connected, F0/0
B 192.168.1.0/24 [20/0] via 172.16.0.1
C 192.168.2.0/24 is directly connected, F2/0
O IA 192.168.3.0/24 [110/2] via 10.0.0.2, F0/0
by Jeremy Stretch
v2.1-r1
Plik z chomika:
Caveman85
Inne pliki z tego folderu:
IBM - TCP-IP Tutorial and Technical Overview.pdf
(6166 KB)
CISCO - Spanning-Tree Protocols (STP RSTP MSTP).pdf
(1161 KB)
physical_terminations.pdf
(381 KB)
Cisco_IOS_Versions.pdf
(67 KB)
VOIP_Basics.pdf
(76 KB)
Inne foldery tego chomika:
• Kurs Cisco CCNA v 3.1
Administrowanie Sieciami Komputerowymi - mgr inż Paweł Pławiak
CCNA
CCNA - CCSP - CNAP - CCSP - Cisco
CCNA - CCSP - CNAP - CCSP - Cisco2
Zgłoś jeśli
naruszono regulamin