I'm wondering if it is possible to configure Cisco ESR to not forward packet over non-MPLS connection(VPI/VCI=0/32) when an LSP for its destination has not been established, while allowing control packets(BGP, LDP, OSPF) to be sent over non-MPLS connection. The reason why I ask about is as follows.
Referring to the following network configuration,
R1 --- Cisco_ESR --- ATM_LSR --- LER --- R2
<--> non-MPLS connection
----------------------->
LSPs
----------------------->
In the ordinary operation, when a packet arrives at Cisco_LER from R1, it gets forwarded over an LSP if available, while getting forwarded over non-MPLS connection(VPI/VCI=0/32) if the corresponding LSP is not available. In the configuration mentioned above,ATM_LSR does software-based packet processing for incoming packet through non-MPLS channel, while doing cell-switching for LSP traffic. Thus if ESR sends packet over non-MPLS connection, e.g, STM-1c, the ATM_LSR could get crashed or time-critical control traffic could be delayed or lost, thereby resulting in BGP/LDP session failure between ESR and ATM_LSR or LER.
In summary, my question is how to prevent Cisco_ESR from forwarding packets over non-MPLS connection when LSPs for their destinations are not available due to LSP failures.
Thanks.
Yongjun.
