ERSPAN Concerns

[Muhammad Anser Khan]

Hi,

I have a requirement to span some sources to the remote destination(recorder).

Both sources and destination are in different subnets connected to different switches.

Sources are connected to  "WS-C3750-48P       12.2(50)SE1           C3750-IPSERVICES-M" but this switch is acting as layer 2. 

Layer 3 (SVI) gateway is on the below switch for source:

Switch(6500)#sh module version

cisco WS-C6509-E

5    2  WS-SUP720-3BXL     SAD0xxxxx Hw : 4.3

                                        Fw : 8.1(3)

                                        Sw : 12.2(18)SXD4

                                        Sw1: 8.4(0.61)RCC6

         WS-SUP720          SAD0xxxxxx Hw : 2.3

                                        Fw : 12.2(17r)S2

                                        Sw : 12.2(18)SXD4

         WS-F6K-PFC3BXL     SADxxxxxxN0 Hw : 1.6

6    2  WS-SUP720-3BXL     SAL0xxxxxx Hw : 4.3

                                        Fw : 8.1(3)

                                        Sw : 12.2(18)SXD4

                                        Sw1: 8.4(0.61)RCC6

         WS-SUP720          SAL0xxxxxU Hw : 2.3

                                        Fw : 12.2(17r)S2

                                        Sw : 12.2(18)SXD4

         WS-F6K-PFC3BXL     SAL09xxxxx Hw : 1.6

The destination is connected to "WS-C3750G-24T      12.2(55)SE9           C3750-IPSERVICESK9-M" but this switch is acting as layer 2.

Layer 3(SVI) gateway is on the below switch for destination:

Switch(4500)#sh module

Chassis Type : WS-C4507R (cat4500-ENTSERVICES-M)

Power consumed by backplane : 40 Watts

Mod Ports Card Type                              Model              Serial No.

---+-----+--------------------------------------+------------------+-----------

1     2  Supervisor IV 1000BaseX (GBIC)         WS-X4515           JAExxxxxx        3.1    12.1(20r)EW1    12.2(50)SG7      Ok      

 2     2  Supervisor IV 1000BaseX (GBIC)         WS-X4515           JAExxxxxx        3.1    12.1(20r)EW1      12.2(50)SG7      Ok

Here are my queries:

1- From the L2 switch (Cisco 3750) till the SVI L3 Switch (Cisco 6500/4500), Will I create RSPAN?

2- From the L3 SVI Switch (Cisco 6500) to the L3 SVI Switch (Cisco 4500). Will I create the ERSPAN? 

But Cisco 4500 does not support ERSPAN. What could be the possible solution?

Below are some hardware limitations:

http://www.cisco.com/c/en/us/support/docs/switches/catalyst-6500-series-switches/10570-41.html

Regards,

Anser

[Aaron Harrison]

Hi

• You have L2 from the 3750 to the 4500.
• You have L3 SVI from 6500 to 4500 - this implies you have a VLAN trunk between these two, but are routing using SVIs.

So in effect, you have L2 capability from the 3750 to the 6500. You could just create an RSPAN VLAN from 3750 through the 4500 to the 6500 and avoid ERSPAN completely.

Aaron

[Muhammad Anser Khan]

Hi Aaron,

I think I did not explain the topology well.

Actually we have Layer 3 P2P link between 6500 and 4500.  (running ospf)

For the source and destination side:

• We have L2 from the 3750 (Destination host) to the 4500 (SVI).
• We have L2 from the 3750 (Source host) the 6500 (SVI).

Here is the flow:

source <L2 3750> gateway < L3 6500> <Layer 3 link P2P> running ospf <Layer 3 link P2P> <L3 4500> gateway < L2 3750> destination.

Kindly suggest

Anser