forming adjacencies using loopback. (eBGP)
advantages:
- dapat terhubung secara logical. ( ga perlu directly connected ).
- loopback ga bisa down, kecuali memang disengaja secara config ( klo port bisa sewaktu2 down ).
disadvantages:
- agak ribet konfigurasi.
- butuh command ebgp-multihop ( pada address yang ga ada di subnet yang sama )
- butuh command update-source loopback
- butuh route kearah loopback address!!
==================
R1
router bgp 100
neighbor 3.3.3.3 remote-as 200
R3
router bgp 200
neighbor 1.1.1.1 remote-as 100
#show ip bgp summary !! bagian up/downnya never.
^ solusi: harus ditambahkan command multihop
R1
conf t
# router bgp 100
# neighbor 3.3.3.3 ebgp-multihop 2 !! jumlah maksimum hop. bs smp 255. tp sebaiknya sekecil mungkin.
# neighbor 3.3.3.3 update-source loopback0
# ip route 3.3.3.3 255.255.255.255 172.12.123.3
R3
conf t
# router bgp 200
# neighbor 1.1.1.1 ebgp-multihop 2
# neighbor 3.3.3.3 update-source loopback0
# ip route 1.1.1.1 255.255.255.255 172.12.123.1
=========================================
Showing posts with label BGP. Show all posts
Showing posts with label BGP. Show all posts
Thursday, March 15, 2018
Wednesday, March 14, 2018
BGP basic documentation ( from christ bryan udemy )
bgp?
" an internet protocol that allows group of routers (AS) to share routing information so that efficient, loop-free routes can be established. "
^ biasanya digunakan di routing antar ISP.
^ masuk dalam kategori EGP / exterior gateway protocol
====================================
BGP :
- support VLSM and summarization
- will send full updates when router first become neighbor, then partial upgrade reflecting latest network change
- create neighbor adjacencies alive. -> no keepalive = adjacencies gone.
=====================================
BGP should be used:
- company connecting more than one AS / ISP.
^ decision on best link / path is by BGP path attributes.
- routing policy of your organization and your ISP differ.
- when ur company is an ISP. when traffic from other AS use your AS as transit domain. (BGP needed! ).
========================================
BGP should not be used:
- when there is a single connection to internet / another AS and no redundant link exist
- when u dont care which path is used to reach a route in another AS
- when router resources are limited ( memory / cpu )
=======================================
BGP Peering Process
- connection oriented ( reliable )
- TCP port 179 !! dont block on acl !!
- exchanges full routes and sync tables, afterward bgp speaker will send further updates only upon change in network
- dont have to be in same AS in order become neighbor / exchange routes.
- BGP adjacencies called " peerings ", BGP peer in same AS = iBGP peer.
==================================
BGP AS100
R1-------------------R2
^ iBGP
-------------------------------------
cisco recommended eBGP peers = directly connected
iBGP peer are not required to be so connected.
=========================================
eBGP
AS100 AS300
R1----------------R3
R1
#conf t
#router bgp 100
#neighbor 172.12.123.3 remote-AS 300
#show ip bgp neigh
!! bgp neighor is 172.12.123.3, remote AS 300, external link !! -> info plg penting
!! bgp state = Active !!
** bgp state
- active = indicates bgp peer connection that does not yet fully exists / does not complete / attempt to peering
- idle = initial state of bgp peering
- Connect follows idle = tcp connection request has been sent but response has not yet been received.
- Idle = if short = normal if stay idle, check remote router's neighbor statement and make sure AS number correct!
- OpenSent = tcp connection complete ( bgp will determines iBGP / eBGP = same as/different AS )
R3
#conf t
#router bgp 300
#neighbor 172.12.123.1 remote-AS 100
# show ip bgp neighbor 172.12.123.1
^
!! bgp neighbor is 172.12.123.1, remote AS 100, external link
!! BGP version 4, remote router ID 172.12.123.1
!! BGP state = Established, up for 00:00:21
!! connection establised 1; dropped 0
!! last reset never
!! local host : 172.12.123.3, local port: 179
!! Foreign host: 172.12.123.1, Foreign port: 28861
^ informasi yg penting ^
R2
#conf t
#router bgp 300
R3
#conf t
#router bgp 100
========================================
" an internet protocol that allows group of routers (AS) to share routing information so that efficient, loop-free routes can be established. "
^ biasanya digunakan di routing antar ISP.
^ masuk dalam kategori EGP / exterior gateway protocol
====================================
BGP :
- support VLSM and summarization
- will send full updates when router first become neighbor, then partial upgrade reflecting latest network change
- create neighbor adjacencies alive. -> no keepalive = adjacencies gone.
=====================================
BGP should be used:
- company connecting more than one AS / ISP.
^ decision on best link / path is by BGP path attributes.
- routing policy of your organization and your ISP differ.
- when ur company is an ISP. when traffic from other AS use your AS as transit domain. (BGP needed! ).
========================================
BGP should not be used:
- when there is a single connection to internet / another AS and no redundant link exist
- when u dont care which path is used to reach a route in another AS
- when router resources are limited ( memory / cpu )
=======================================
BGP Peering Process
- connection oriented ( reliable )
- TCP port 179 !! dont block on acl !!
- exchanges full routes and sync tables, afterward bgp speaker will send further updates only upon change in network
- dont have to be in same AS in order become neighbor / exchange routes.
- BGP adjacencies called " peerings ", BGP peer in same AS = iBGP peer.
==================================
BGP AS100
R1-------------------R2
^ iBGP
-------------------------------------
cisco recommended eBGP peers = directly connected
iBGP peer are not required to be so connected.
=========================================
eBGP
AS100 AS300
R1----------------R3
R1
#conf t
#router bgp 100
#neighbor 172.12.123.3 remote-AS 300
#show ip bgp neigh
!! bgp neighor is 172.12.123.3, remote AS 300, external link !! -> info plg penting
!! bgp state = Active !!
** bgp state
- active = indicates bgp peer connection that does not yet fully exists / does not complete / attempt to peering
- idle = initial state of bgp peering
- Connect follows idle = tcp connection request has been sent but response has not yet been received.
- Idle = if short = normal if stay idle, check remote router's neighbor statement and make sure AS number correct!
- OpenSent = tcp connection complete ( bgp will determines iBGP / eBGP = same as/different AS )
R3
#conf t
#router bgp 300
#neighbor 172.12.123.1 remote-AS 100
# show ip bgp neighbor 172.12.123.1
^
!! bgp neighbor is 172.12.123.1, remote AS 100, external link
!! BGP version 4, remote router ID 172.12.123.1
!! BGP state = Established, up for 00:00:21
!! connection establised 1; dropped 0
!! last reset never
!! local host : 172.12.123.3, local port: 179
!! Foreign host: 172.12.123.1, Foreign port: 28861
^ informasi yg penting ^
R2
#conf t
#router bgp 300
R3
#conf t
#router bgp 100
========================================
BGP basic documentation
BGP INE documentation.
-> Exterior Gateway Protocol
-advertise learn and choose best path inside.
-used by ISP to exchange routing information between themselves
enterprise use bgp to exchange routing info with 1 or more isp
====================================
OSPF EIGRP / IGP -> 4000 route mulai ga kuat.
IGP:
EIGRP - DUAL ( SUCCESOR , FEASIBLE SUCCESSOR )
OSPF - SPF algorithm.
distance
hop count
cost
install on routing table
+ bisa s/d 4 equal path cost load balancing
----------------
BGP - robust best-path algorithm
- check different attributes for path determination.
best route installed on routing table!
===================================
core router butuh tau semua routingannya!
12000 subnet in my network!
==================================
similarities bgp and igp (ospf & eigrp )
- need form adjacencies
- need to advertise prefix
- advertise next hop for those prefix
disimilarities
- neighbor ip address may not be on common subnet
- BGP USE TCP port 179 between neighbors. IGP do not use tcp
==================================
BGP advertised prefix / length = NLRI ( network layer reachability information )
IGP - lebih ke fast convergence , best path determination ( efficient route )
BG
P - scalability ( carry load > 1000 routes !! )
BGP use path vector logic ( similar to distance vector )
=================================
iBGP & eBGP
ada yg bisa dilakukan di iBGP yang tidak bisa dilakukan di eBGP, begitu juga sebaliknya.
same AS = iBGP
different AS = eBGP
AS number harus unique.
dapet dari ISP biasanya.
#router bgp 65350
^ klo di router tetangga juga 65350 tandanya IBGP.
=================================
bgp AS_PATH -- berbeda antara ibgp dan ebgp.
BGP- EVERYTHING IS UNICAST!
=================================
SP-1 SP-2 SP-3
ebgp
AS 1000 ----- AS2000 AS3000
R1 R3-R4-R5 R7
eigrp ibgp
R2 R6
R3-R4-R5 : IBGP
r3 ga harus terhubung directly ke r5 untuk formed adjacencies ibgp.
network-x di R1 ---> eigrp ke R2
diinject ke ebgp ke AS 2000 di R3 ( ebgp update )
send update keluar AS number lain hrs punya as-path
R2 as-path = 1000
R3-R4-R5 harus mempertahankan as-path buat network x
R3 as-path = 1000
R5 buat advertise network x ke external peer R6 harus ganti as-path sesuai as-pathnya
R5 as-path = 2000 1000
R6 advertise IBGP ke R7 as-pathnya sama
R6 as-path = 2000 1000
================================
contoh as path:
x.x.x.x/24 23 4000 56 702
x.x.x.x/24 = route sampe ke local
23 = as number 1
4000 = as number 2
56 = as number 3
702 = as number 4
=============================
intinya pas advertise:
ibgp harus sama as-pathnya ( dipertahankan )
ebgp harus add as-path AS number local
============================
public AS di internet:
1- 64495
private AS:
65512 - 65534
reserved AS ( ga bisa dipake ):
0
54496 -65511
65535
===========================
scenario 1 dikasih public ip.
SP ---- AS 2000
R1
|
|
|
COMPANY A ----- AS
R2 , R3, R4, R5, R6
R2
ip route 0.0.0.0 0.0.0.0 R1
misal dikasih ip range 200.200.200.x/24 -> disubnet ke network local.
yg advertise ke internet tanggung jawab sisi bagian SP.
as number 2000 advertise 200.200.200.x keluar.
=========================
scenario 2 bikin bgp peer.
- ambil 1 private AS number. trus bikin bgp peer ke router ISP.
SP ---- AS 2000
R1
|
|
|
COMPANY A ----- AS
R2 , R3, R4, R5, R6
R2 ---- AS 65512
dari ISP nanti bakal nyatet private AS si customer.
ketika berhubungan dengan ISP lainnya AS number private
si customer bakal di strip.
=======================
klo ada 2 SP di customer.
butuh beli AS number.
=========================
16 bit AS -> ccnp topic
32 bit AS -> ccie topic
=========================
eBGP neighborship
1. form neighborship
2. exchange topology info
3. run best-path algorithm
- form neighborship using port 179 TCP
- eBGP neighbors assumed to be directly connected. ( bisa via igp routenya )
eBGP neighborship requirement
- local bgp as number must match neighbor router as number
- peer must be reachable via IGP route
- bgp router id 2 router must not be same
- authentication md5 must pass ( if configured )
========================
**configure eBGP neighbors
#router bgp [asn]
neighbor [ip-address] remote-as [remote-asn]
** configure router-ID
#bgp router-id x.x.x.x
^ klo ga diconfig by default bakal ngambil highest loopback ip address.
^ klo ga config loopback, bakal ngambil highest ip address interface.
** configure BGP authentication ( harus diconfigure di 2 router bersangkutan )
#neighbor [neighbor-ip] [password-key]
ex:
conf t
router bgp 2
neighbor 1.1.1.1 password 0 cisco123
^ 0 maksudnya kita masukin dalam bentuk normal text yg nanti di encrypt ke md5
^ bisa dibikin 7 tp masukin password cisco123nya dalam bentuk md5
conf t
router bgp 1
neighbor 1.1.1.2 password 0 cisco123
** verify command
#show ip bgp neighbor !! cari BGP state = established
=======================
-> Exterior Gateway Protocol
-advertise learn and choose best path inside.
-used by ISP to exchange routing information between themselves
enterprise use bgp to exchange routing info with 1 or more isp
====================================
OSPF EIGRP / IGP -> 4000 route mulai ga kuat.
IGP:
EIGRP - DUAL ( SUCCESOR , FEASIBLE SUCCESSOR )
OSPF - SPF algorithm.
distance
hop count
cost
install on routing table
+ bisa s/d 4 equal path cost load balancing
----------------
BGP - robust best-path algorithm
- check different attributes for path determination.
best route installed on routing table!
===================================
core router butuh tau semua routingannya!
12000 subnet in my network!
==================================
similarities bgp and igp (ospf & eigrp )
- need form adjacencies
- need to advertise prefix
- advertise next hop for those prefix
disimilarities
- neighbor ip address may not be on common subnet
- BGP USE TCP port 179 between neighbors. IGP do not use tcp
==================================
BGP advertised prefix / length = NLRI ( network layer reachability information )
IGP - lebih ke fast convergence , best path determination ( efficient route )
BG
P - scalability ( carry load > 1000 routes !! )
BGP use path vector logic ( similar to distance vector )
=================================
iBGP & eBGP
ada yg bisa dilakukan di iBGP yang tidak bisa dilakukan di eBGP, begitu juga sebaliknya.
same AS = iBGP
different AS = eBGP
AS number harus unique.
dapet dari ISP biasanya.
#router bgp 65350
^ klo di router tetangga juga 65350 tandanya IBGP.
=================================
bgp AS_PATH -- berbeda antara ibgp dan ebgp.
BGP- EVERYTHING IS UNICAST!
=================================
SP-1 SP-2 SP-3
ebgp
AS 1000 ----- AS2000 AS3000
R1 R3-R4-R5 R7
eigrp ibgp
R2 R6
R3-R4-R5 : IBGP
r3 ga harus terhubung directly ke r5 untuk formed adjacencies ibgp.
network-x di R1 ---> eigrp ke R2
diinject ke ebgp ke AS 2000 di R3 ( ebgp update )
send update keluar AS number lain hrs punya as-path
R2 as-path = 1000
R3-R4-R5 harus mempertahankan as-path buat network x
R3 as-path = 1000
R5 buat advertise network x ke external peer R6 harus ganti as-path sesuai as-pathnya
R5 as-path = 2000 1000
R6 advertise IBGP ke R7 as-pathnya sama
R6 as-path = 2000 1000
================================
contoh as path:
x.x.x.x/24 23 4000 56 702
x.x.x.x/24 = route sampe ke local
23 = as number 1
4000 = as number 2
56 = as number 3
702 = as number 4
=============================
intinya pas advertise:
ibgp harus sama as-pathnya ( dipertahankan )
ebgp harus add as-path AS number local
============================
public AS di internet:
1- 64495
private AS:
65512 - 65534
reserved AS ( ga bisa dipake ):
0
54496 -65511
65535
===========================
scenario 1 dikasih public ip.
SP ---- AS 2000
R1
|
|
|
COMPANY A ----- AS
R2 , R3, R4, R5, R6
R2
ip route 0.0.0.0 0.0.0.0 R1
misal dikasih ip range 200.200.200.x/24 -> disubnet ke network local.
yg advertise ke internet tanggung jawab sisi bagian SP.
as number 2000 advertise 200.200.200.x keluar.
=========================
scenario 2 bikin bgp peer.
- ambil 1 private AS number. trus bikin bgp peer ke router ISP.
SP ---- AS 2000
R1
|
|
|
COMPANY A ----- AS
R2 , R3, R4, R5, R6
R2 ---- AS 65512
dari ISP nanti bakal nyatet private AS si customer.
ketika berhubungan dengan ISP lainnya AS number private
si customer bakal di strip.
=======================
klo ada 2 SP di customer.
butuh beli AS number.
=========================
16 bit AS -> ccnp topic
32 bit AS -> ccie topic
=========================
eBGP neighborship
1. form neighborship
2. exchange topology info
3. run best-path algorithm
- form neighborship using port 179 TCP
- eBGP neighbors assumed to be directly connected. ( bisa via igp routenya )
eBGP neighborship requirement
- local bgp as number must match neighbor router as number
- peer must be reachable via IGP route
- bgp router id 2 router must not be same
- authentication md5 must pass ( if configured )
========================
**configure eBGP neighbors
#router bgp [asn]
neighbor [ip-address] remote-as [remote-asn]
** configure router-ID
#bgp router-id x.x.x.x
^ klo ga diconfig by default bakal ngambil highest loopback ip address.
^ klo ga config loopback, bakal ngambil highest ip address interface.
** configure BGP authentication ( harus diconfigure di 2 router bersangkutan )
#neighbor [neighbor-ip] [password-key]
ex:
conf t
router bgp 2
neighbor 1.1.1.1 password 0 cisco123
^ 0 maksudnya kita masukin dalam bentuk normal text yg nanti di encrypt ke md5
^ bisa dibikin 7 tp masukin password cisco123nya dalam bentuk md5
conf t
router bgp 1
neighbor 1.1.1.2 password 0 cisco123
** verify command
#show ip bgp neighbor !! cari BGP state = established
=======================
Tuesday, March 13, 2018
BGP Basic Documentation part 1
BGP
" an internet protocol that allows group of routers (AS) to share routing information so that efficient, loop-
free routes can be established. "
^ biasanya digunakan di routing antar ISP.
^ masuk dalam kategori EGP / exterior gateway protocol
====================================
BGP :
- support VLSM and summarization
- will send full updates when router first become neighbor, then partial upgrade reflecting latest network change
- create neighbor adjacencies alive. -> no keepalive = adjacencies gone.
=====================================
BGP should be used:
- company connecting more than one AS / ISP.
^ decision on best link / path is by BGP path attributes.
- routing policy of your organization and your ISP differ.
- when ur company is an ISP. when traffic from other AS use your AS as transit domain. (BGP needed! ).
========================================
BGP should not be used:
- when there is a single connection to internet / another AS and no redundant link exist
- when u dont care which path is used to reach a route in another AS
- when router resources are limited ( memory / cpu )
=======================================
BGP Peering Process
- connection oriented ( reliable )
- TCP port 179 !! dont block on acl !!
- exchanges full routes and sync tables, afterward bgp speaker will send further updates only upon change in
network
- dont have to be in same AS in order become neighbor / exchange routes.
- BGP adjacencies called " peerings ", BGP peer in same AS = iBGP peer.
==================================
BGP AS100
R1-------------------R2
^ iBGP
-------------------------------------
cisco recommended eBGP peers = directly connected
iBGP peer are not required to be so connected.
=========================================
eBGP
AS100 AS300
R1----------------R3
R1
#conf t
#router bgp 100
#neighbor 172.12.123.3 remote-AS 300
#show ip bgp neigh
!! bgp neighor is 172.12.123.3, remote AS 300, external link !! -> info plg penting
!! bgp state = Active !!
** bgp state
- active = indicates bgp peer connection that does not yet fully exists / does not complete / attempt to peering
- idle = initial state of bgp peering
- Connect follows idle = tcp connection request has been sent but response has not yet been received.
- Idle = if short = normal if stay idle, check remote router's neighbor statement and make sure AS number
correct!
- OpenSent = tcp connection complete ( bgp will determines iBGP / eBGP = same as/different AS )
R3
#conf t
#router bgp 300
#neighbor 172.12.123.1 remote-AS 100
# show ip bgp neighbor 172.12.123.1
^
!! bgp neighbor is 172.12.123.1, remote AS 100, external link
!! BGP version 4, remote router ID 172.12.123.1
!! BGP state = Established, up for 00:00:21
!! connection establised 1; dropped 0
!! last reset never
!! local host : 172.12.123.3, local port: 179
!! Foreign host: 172.12.123.1, Foreign port: 28861
^ informasi yg penting ^
R2
#conf t
#router bgp 300
R3
#conf t
#router bgp 100
========================================
" an internet protocol that allows group of routers (AS) to share routing information so that efficient, loop-
free routes can be established. "
^ biasanya digunakan di routing antar ISP.
^ masuk dalam kategori EGP / exterior gateway protocol
====================================
BGP :
- support VLSM and summarization
- will send full updates when router first become neighbor, then partial upgrade reflecting latest network change
- create neighbor adjacencies alive. -> no keepalive = adjacencies gone.
=====================================
BGP should be used:
- company connecting more than one AS / ISP.
^ decision on best link / path is by BGP path attributes.
- routing policy of your organization and your ISP differ.
- when ur company is an ISP. when traffic from other AS use your AS as transit domain. (BGP needed! ).
========================================
BGP should not be used:
- when there is a single connection to internet / another AS and no redundant link exist
- when u dont care which path is used to reach a route in another AS
- when router resources are limited ( memory / cpu )
=======================================
BGP Peering Process
- connection oriented ( reliable )
- TCP port 179 !! dont block on acl !!
- exchanges full routes and sync tables, afterward bgp speaker will send further updates only upon change in
network
- dont have to be in same AS in order become neighbor / exchange routes.
- BGP adjacencies called " peerings ", BGP peer in same AS = iBGP peer.
==================================
BGP AS100
R1-------------------R2
^ iBGP
-------------------------------------
cisco recommended eBGP peers = directly connected
iBGP peer are not required to be so connected.
=========================================
eBGP
AS100 AS300
R1----------------R3
R1
#conf t
#router bgp 100
#neighbor 172.12.123.3 remote-AS 300
#show ip bgp neigh
!! bgp neighor is 172.12.123.3, remote AS 300, external link !! -> info plg penting
!! bgp state = Active !!
** bgp state
- active = indicates bgp peer connection that does not yet fully exists / does not complete / attempt to peering
- idle = initial state of bgp peering
- Connect follows idle = tcp connection request has been sent but response has not yet been received.
- Idle = if short = normal if stay idle, check remote router's neighbor statement and make sure AS number
correct!
- OpenSent = tcp connection complete ( bgp will determines iBGP / eBGP = same as/different AS )
R3
#conf t
#router bgp 300
#neighbor 172.12.123.1 remote-AS 100
# show ip bgp neighbor 172.12.123.1
^
!! bgp neighbor is 172.12.123.1, remote AS 100, external link
!! BGP version 4, remote router ID 172.12.123.1
!! BGP state = Established, up for 00:00:21
!! connection establised 1; dropped 0
!! last reset never
!! local host : 172.12.123.3, local port: 179
!! Foreign host: 172.12.123.1, Foreign port: 28861
^ informasi yg penting ^
R2
#conf t
#router bgp 300
R3
#conf t
#router bgp 100
========================================
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