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ASR1002 BGP routing Prefix And TX Droping Traffic

Hi Dear Friend I have Router ASR1002 by multi Bgp Session Now i want if bgp peers announce prefix to me for example

announce prefix 192.168.0.0/24 to me My ASR 1002 Allow Forward TX traffic (send) by this Source From own automacticlly any prefix announce to me my router allow Cross Traffic Send From Own to uplink .

Please help me

6 Replies 6

MHM Cisco World
Advisor
Advisor

make other peer send MED or Path Prepend with prefix this make your ASR prefer it than other subnet. 

new-cisco.jpg

 

For example in this Senario IF Customer announce prefix ( ip range ) x.x.x.x/y To ASR1002 ( internet Edge router ) ASR allow traffic send to the internet of this range ( for sysnc path user )

Now i want  if announce by bgp  to me the prefix . my ASR1002X allow Cross traffic TX (send ) to the internet and if donnot announce to me by bgp my ASR1002X DROP the traffic tx (send to the internet ) uplink of the prefix

Hello admin@atrinnet.net ,

>> Now i want if announce by bgp to me the prefix . my ASR1002X allow Cross traffic TX (send ) to the internet and if donnot announce to me by bgp my ASR1002X DROP the traffic tx (send to the internet ) uplink of the prefix

 

You can use uRPF in strict mode for this. In this way incoming packets are examined and if the source best path is not via the rx interface the packet is dropped.

 

WARNING : uRPF in strict mode can create problems for multi homed customers.

 

Hope to help

Giuseppe

 

MHM Cisco World
Advisor
Advisor

As I get the costumer use some kind of default/static route and forward traffic toward ASR, 

ASR must  get prefix from costumer before forward traffic if not then the return traffic will drop at ASR.

make any routing protocol between the costumer and ASR,

ASR will advertise default to costumer which will use it to forward traffic, and costumer will advertise it prefix,

if for some reason the routing protocol not work then the ASR will not advertise the default and costumer not advertise it prefix and hence the forward traffic and asymmetric is prevent. 

Thank For attention But please Read My Question Carefully

I donnot Advertise  Default route or any route to customer

Cutomer Announce to me Ip address and me Redistibuted to My upstream bgp sessions

Customer have 2 internet uplinks by 2 ISP my ASR Router and another ISP

I want have policy On bgp session  Of Customer that IF customer announce to me own prefix X.X.X.X/y on bgp and send to me traffic send ( Set my Inter VLAN ip address default gateway ) my router CRoss Traffic TX ( Send ) to the internet  otherwise Drop Traffic TX ( send to the internet ) customer for example by source ip address X.X.X.1

 

Thanks

why costumer select send traffic through ASR ? 

ASR policy can control the Outbound, the Inbound is control from the costumer.

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