Cisco Cisco Packet Data Gateway (PDG) Fehlerbehebungsanleitung

GRE Protocol Interface

How GRE Interface Support Works ▀

Cisco ASR 5000 Series Enhanced Feature Configuration Guide ▄

OL-22983-01

Figure 8.

Ingress Packet Processing on GRE Interface

Normal flow processing

based on inner IP packet,

in the VRF indicated by

the flow record of previous

successful flow record

Lookup

Successful?

End

Yes

Forwarding lookup

in the VRF

End

Is the packet

destined to our

chassis?

If tunneled packet

flag set, re-attach

header and send it

to kernel

Send the packet to

the kernel without
the tunnel header

for further

processing

Yes

Start

Processing of other

type of packets

Yes

Lookup based on

outer DA-SA and is it

GRE

Is it a GRE

Keepalive?

Send packet to

configured VPN

mgr

Does received GRE

have Sequence

Number, CRC or GRE

Key?

Yes

Drop packet

Set received tunneled packet flag

Get Flow Record.

(Tunnel header and VRF number )

Process the PPB.

1. Remove the outer IPV4 header and GRE header

2. Use the VRF number to further lookups.

Send packet to

configured session

manager

Yes