RSVP-Previous Hop Overwrite

Flexibility and Customization

You can configure a CE to populate the PHOP object in a PATH message with an address that is reachable in the customer VPN. This enables the RESV message to find its way back towards the sender so that reservations can be established.

Perform this task to configure a source address or a source interface.

The figure below shows a sample network in which PHOP is configured.

Figure 2

Sample PHOP Network

Configuring a Source Address on Router CE1 for the CE1-to-PE1 Interface

The following example configures a source address on the CE1-to-PE1 (Ethernet 1/0) interface in the figure above:

Router(CE1)# configure terminal
 
Enter configuration commands, one per line.  End with CNTL/Z.
Router(CE1)(config)# interface ethernet 1/0
Router(CE1)(config-if)# ip rsvp source address 10.2.2.2
 <--------------------
Router(CE1)(config-if)# end

Configuring a Source Address on Router CE2 for the CE2-to-PE2 Interface

The following example configures a source address on the CE2-to-PE2 (Ethernet 0/0) interface in the figure above:

Router(CE2)# configure terminal
 
Enter configuration commands, one per line.  End with CNTL/Z.
Router(CE2)(config)# interface ethernet 0/0
Router(CE2)(config-if)# ip rsvp source address 10.6.6.6
 <---------------------
Router(CE2)(config-if)# end

Creating a Listener Proxy on Router C2

The following example creates a listener proxy on Router C2 and requests that the receiver reply with a RESV message for the flow if the PATH message destination is 10.7.7.7 in the figure above:

Router(C2)# configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router(C2)(config)# ip rsvp listener 10.7.7.7 any any reply <--------------------
Router(C2)(config)# end

Creating a Session from Router C1 to Router C2

The following example creates an RSVP session from Router C1 to Router C2:

Router(C1)# configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router(C1)(config)# ip rsvp sender-host 10.7.7.7 10.1.1.1 UDP 100 200 1 1 <-------------
Router(C1)(config)# end

Verifying the Source Address on Router CE1 for the CE1-to-PE1 Interface

The following example verifies the source address (10.2.2.2) configured on the CE1-to-PE1 (Ethernet 1/0) interface in the figure below:

Router(CE1)# show ip rsvp interface detail ethernet 1/0
 Et1/0:
   RSVP: Enabled
   Interface State: Up
   Bandwidth:
     Curr allocated: 1K bits/sec
     Max. allowed (total): 100K bits/sec
     Max. allowed (per flow): 100K bits/sec
     Max. allowed for LSP tunnels using sub-pools: 0 bits/sec
     Set aside by policy (total): 0 bits/sec
   Admission Control:
     Header Compression methods supported:
       rtp (36 bytes-saved), udp (20 bytes-saved)
   Traffic Control:
     RSVP Data Packet Classification is ON via CEF callbacks
   Signalling:
     DSCP value used in RSVP msgs: 0x3F
     Number of refresh intervals to enforce blockade state: 4
     Ip address used in RSVP objects: 10.2.2.2 <------------------------------------
   Authentication: disabled
     Key chain:   <none>
     Type:        md5
     Window size: 1
     Challenge:   disabled 
   Hello Extension:
     State: Disabled

Verifying the Source Address on Router CE2 for the CE2-to-PE2 Interface

The following example verifies the source address configured on the CE2-to-PE2 (Ethernet 0/0) interface in the figure below:

Router(CE2)# show ip rsvp interface detail ethernet 0/0
 Et0/0:
   RSVP: Enabled
   Interface State: Up
   Bandwidth:
     Curr allocated: 0 bits/sec
     Max. allowed (total): 100K bits/sec
     Max. allowed (per flow): 100K bits/sec
     Max. allowed for LSP tunnels using sub-pools: 0 bits/sec
     Set aside by policy (total): 0 bits/sec
   Admission Control:
     Header Compression methods supported:
       rtp (36 bytes-saved), udp (20 bytes-saved)
   Traffic Control:
     RSVP Data Packet Classification is ON via CEF callbacks
   Signalling:
     DSCP value used in RSVP msgs: 0x3F
     Number of refresh intervals to enforce blockade state: 4
     Ip address used in RSVP objects: 10.6.6.6 <-----------------------------------
   Authentication: disabled
     Key chain:   <none>
     Type:        md5
     Window size: 1
     Challenge:   disabled 
   Hello Extension:
     State: Disabled

Verifying the Listener Proxy on Router C2

The following example verifies the listener proxy configured on Router C2 in the figure below:

Router(C2)# show ip rsvp listeners
To                Protocol   DPort   Description                 Action
10.7.7.7 <-------- any        any     RSVP Proxy                  reply

Verifying the Session from Router C1 to Router C2

The following example verifies that the session configured between Router C1 and Router C2 in the figure below is up:

Router(C1)# show ip rsvp reservation
To              From          Pro DPort Sport Next Hop      I/F      Fi Serv BPS
10.7.7.7       10.1.1.1       UDP 100   200   10.1.2.21     Et0/0    FF RATE 1K

Verifying the PHOP Address

The following example on Router CE2 verifies the source address configured on the CE1-to-PE1 interface in the figure below as the PHOP address:

Router(CE2)# show ip rsvp sender detail
PATH:
  Destination 10.7.7.7, Protocol_Id 17, Don't Police , DstPort 100
  Sender address: 10.1.1.1, port: 200
  Path refreshes:
    arriving: from PHOP 10.2.2.2 on Et0/0 every 30000 msecs <-------------------
  Traffic params - Rate: 1K bits/sec, Max. burst: 1K bytes
    Min Policed Unit: 0 bytes, Max Pkt Size 2147483647 bytes
  Path ID handle: CA000406.
  Incoming policy: Accepted. Policy source(s): Default
  Status:
  Output on Ethernet1/0. Policy status: Forwarding. Handle: 0E000402
    Policy source(s): Default

Verifying the Next-Hop Address

The following example on Router CE1 verifies the source address configured on the CE2-to-PE2 interface in the figure below as the next-hop address:

Router(CE1)# show ip rsvp reservation detail
RSVP Reservation. Destination is 10.7.7.7, Source is 10.1.1.1, 
  Protocol is UDP, Destination port is 100, Source port is 200
  Next Hop: 10.6.6.6 on Ethernet1/0 <---------------------------------------------
  Reservation Style is Fixed-Filter, QoS Service is Guaranteed-Rate
  Resv ID handle: 03000400.
  Created: 07:01:40 IST Tue Mar 25 2008
  Average Bitrate is 1K bits/sec, Maximum Burst is 1K bytes
  Min Policed Unit: 0 bytes, Max Pkt Size: 0 bytes
  Status:
  Policy: Forwarding. Policy source(s): Default