Cisco Cisco StadiumVision Mobile Streamer Maintenance Manual

In the three-layer design, only the distribution switch contains the “ip helper-
address” configuration for the VLAN interface to forward the DHCP requests to 
CNR. 

If DHCP snooping is enabled on both the Distribution and Access Layer 
switches, DHCP snooping on the Distribution switch will drop DHCP packets that 
have the option-82 information appended to the DHCP data. To allow the DHCP 
packets to be forwarded or relayed by the Distribution switch to CNR via the ip-
helper address command, the VLAN interface must be configured to trust the 
Option 82 information, as illustrated in the following example. 

interface Vlan200 
  description DMP VLAN 
  ip dhcp relay information trusted 

ß only required if DHCP Snooping is on

 

both the Distribution and Access Switches 
  ip address 10.60.2.1 255.255.255.0 
  ip helper-address 10.50.1.254 
  ip pim passive 

Below is an example of properly configured DHCP snooping with one trusted 
uplink: 

 

Switch>show ip dhcp snooping 
Switch DHCP snooping is enabled     

ß result of “ip dhcp snooping”

 

DHCP snooping is configured on following VLANs: 
10                                  

ß result of “ip dhcp snooping vlan 10”

 

DHCP snooping is configured on the following Interfaces: 
 
Insertion of option 82 is enabled 
   circuit-id format: vlan-mod-port 
    remote-id format: MAC 
Option 82 on untrusted port is not allowed 
Verification of hwaddr field is enabled 
Interface                    Trusted     Rate limit (pps) 
------------------------     -------     ----------- 
GigabitEthernet0/47          yes         unlimited  

ß result of “ip dhcp snooping trusted”

 

 
 
Switch>show ip dhcp snooping binding  
MacAddress          IpAddress        Lease(sec)  Type           VLAN  Interface 
------------------  ---------------  ----------  -------------  ----  ----------- 
00:0F:44:01:0E:95   172.16.102.6     429171      dhcp-snooping   10    GigabitEthernet0/33 
00:0F:44:01:0E:49   172.16.102.4     427725      dhcp-snooping   10    GigabitEthernet0/1 
00:0F:44:01:41:00   172.16.102.29    604686      dhcp-snooping   10    GigabitEthernet0/31 
00:0F:44:01:0E:C6   172.16.102.10    493607      dhcp-snooping   10    GigabitEthernet0/7 
00:0F:44:01:0E:97   172.16.102.3     426769      dhcp-snooping   10    GigabitEthernet0/35 
00:0F:44:01:0E:9E   172.16.102.7     590252      dhcp-snooping   10    GigabitEthernet0/15 
Total number of bindings: 6