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bgp announce /24

hi

we re-config the bgp and we would like to have as following:

for provider A

200.1.0.0/24

200.1.1.0/24

200.1.2.0/23

for provider B

200.1.0.0/24

200.1.1.0/24

200.1.2.0/24

200.1.3.0/24

we find that the router always announces /23 to provider B. How do we send four routes? pls advice

----

router bgp 30x

!

network 200.1.0.0

network 200.1.1.0

network 200.1.2.0 mask 255.255.254.0

neighbor 202.1.1.1 route-map Set_ASN_PB out

!

ip route 200.1.2.0 mask 255.255.254.0 null0 250

!

!

!

access-list 20 permit 200.1.0.0 0.0.0.255

access-list 20 permit 200.1.1.0 0.0.0.255

access-list 20 permit 200.1.2.0 0.0.0.255

access-list 20 permit 200.1.3.0 0.0.0.255

!

ip as-path access-list 130 deny .*

ip as-path access-list 130 permit ^$

!

!

route-map Set_ASN_PB permit 10

match ip address 20

!

route-map Set_ASN_PB permit 30

match as-path 130

!

---

BGP table version is 248, local router ID is 10.254.210.1

Status codes: s suppressed, d damped, h history, * valid, > best, i - internal

Origin codes: i - IGP, e - EGP, ? - incomplete

Network Next Hop Metric LocPrf Weight Path

*> 200.1.0.0 0.0.0.0 0 32768 i

*> 200.1.1.0 0.0.0.0 0 32768 i

*> 200.1.2.0/23 0.0.0.0 0 32768 i

2 ACCEPTED SOLUTIONS

Accepted Solutions
Cisco Employee

Re: bgp announce /24

Please see the response to you other posting.

http://forums.cisco.com/eforum/servlet/NetProf?page=netprof&forum=Network%20Infrastructure&topic=WAN%2C%20Routing%20and%20Switching&CommCmd=MB%3Fcmd%3Dpass_through%26location%3Doutline%40%5E1%40%40.1ddf22e4/18#selected_message

Regards,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México 
Paseo de la Reforma 222 Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
Silver

Re: bgp announce /24

If you want to advertise all four routes, do a:

router bgp 30x

!

network 200.1.0.0

network 200.1.1.0

no network 200.1.2.0 mask 255.255.254.0

network 200.1.2.0

network 200.1.3.0

aggregate-address 200.1.2.0 mask 255.255.254.0

neighbor providerA route-map Set_ASN_PA out

neighbor providerB route-map Set_ASN_PB out

!

!

ip prefix-list ProviderA seq 10 permit 200.1.0.0/23 ge 24

ip prefix-list ProviderA seq 20 permit 200.1.2.0/23

ip prefix-list ProviderB seq 10 permit 200.1.0.0/22 ge 24

route-map Set_ASN_PA permit 10

match ip address prefix-list ProviderA

!

route-map Set_ASN_PA permit 30

match as-path 130

route-map Set_ASN_PB permit 10

match ip address prefix-list ProviderB

!

route-map Set_ASN_PB permit 30

match as-path 130

This way, in routing table you will have /24 and /23 routes, but route-map will advertise only /24 to provider B, and /24 and /23 to provider A.

3 REPLIES
Cisco Employee

Re: bgp announce /24

Please see the response to you other posting.

http://forums.cisco.com/eforum/servlet/NetProf?page=netprof&forum=Network%20Infrastructure&topic=WAN%2C%20Routing%20and%20Switching&CommCmd=MB%3Fcmd%3Dpass_through%26location%3Doutline%40%5E1%40%40.1ddf22e4/18#selected_message

Regards,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México 
Paseo de la Reforma 222 Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
Silver

Re: bgp announce /24

You should use 200.1.0.0/22 Use.

It will conver your subnets

200.1.0.0/24

200.1.1.0/24

200.1.2.0/24

200.1.3.0/24

For 200.1.2.0/23, Advertise separately also. Because it covers more hosts than 200.1.2.0/24.

Or You can advertise that by Concept " periodic downloaded static route ".

Above routing table is true according to route aggregation.

Regards,

Dharmesh Purohit

Silver

Re: bgp announce /24

If you want to advertise all four routes, do a:

router bgp 30x

!

network 200.1.0.0

network 200.1.1.0

no network 200.1.2.0 mask 255.255.254.0

network 200.1.2.0

network 200.1.3.0

aggregate-address 200.1.2.0 mask 255.255.254.0

neighbor providerA route-map Set_ASN_PA out

neighbor providerB route-map Set_ASN_PB out

!

!

ip prefix-list ProviderA seq 10 permit 200.1.0.0/23 ge 24

ip prefix-list ProviderA seq 20 permit 200.1.2.0/23

ip prefix-list ProviderB seq 10 permit 200.1.0.0/22 ge 24

route-map Set_ASN_PA permit 10

match ip address prefix-list ProviderA

!

route-map Set_ASN_PA permit 30

match as-path 130

route-map Set_ASN_PB permit 10

match ip address prefix-list ProviderB

!

route-map Set_ASN_PB permit 30

match as-path 130

This way, in routing table you will have /24 and /23 routes, but route-map will advertise only /24 to provider B, and /24 and /23 to provider A.

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