[ixpmanager] IXPManager: Two customers on one port

Wed Apr 22 09:23:21 IST 2026

Hi Salvador,

On 21/04/2026 23:57:54, "Salvador Bertenbreiter" <salvadorb at gmail.com> 
wrote:

>What we have been using a two-switch (fan-out) approach (although I 
>suspect it's not the optimal path).
>
>1) Assign a dedicated (or shared) switch as "demux" switch. In this 
>device, we connect the reseller(s) interface(s) and "demux" each VLAN 
>to a dedicated physical port for each customer. This was our solution 
>to solve the same bridging domain issue when we only used VLAN 
>translation. The configuration on this device is, for example: Carrier 
>X's port is configured in switchport and trunk mode, and a dedicated 
>VLAN ID is assigned for each customer that they transport. Then, a 
>physical port for each customer is physically connected from the demux 
>switch to the IXP switch, and in the demux switch, each customer port 
>is configured in access mode associated with the VLAN ID used in the 
>reseller port.

It sounds very similar to what the method we and others have used, 
except we have just fanned out and back to the same switch. E.g.:

Eth1: reseller uplink with two customers, A tagged with 2001, and B 
tagged with 2002

Eth2: Access port for vlan 2001 (i.e., cust A’s traffic to/from the 
reseller uplink flows here), and this is connected directly to:
Eth3: Access port for peering LAN, completing cust A’s connection to the 
IXP.

Eth4: Access port for vlan 2002 (i.e., cust B’s traffic to/from the 
reseller uplink flows here), and this is connected directly to:
Eth5: Access port for peering LAN, completing cust B’s connection to the 
IXP.

>Is the subinterface method a better method to replace fanout ports?

Well, it’s better in that your reseller connection is the only physical 
connection you need, so you are not burning two additional ports per 
member. However, first your switch needs to support subinterfaces in the 
way this works, and then that subinterface implementation on your switch 
needs to support all the features you rely on that your physical 
interfaces do.

>  If so, would that run on any HW platform (Tomahawk-based switch for 
>example), or are more advanced ASICs like Jericho required? We also use 
>mainly Arista as our IXP switches.

We also use Arista, and our models support it. I know we, along with 
LONAP, and perhaps others, worked with Arista to get this feature 
implemented appropriately for IXPs. Let me see if I can get a more 
detailed reply on the technical specifics.

  - Barry

>
>Best regards,
>
>El mar, 21 abr 2026 a la(s) 10:55 a.m., Barry O'Donovan (INEX) via 
>ixpmanager (ixpmanager at inex.ie) escribió:
>>
>>Hi Roland,
>>
>>Yes, this is the perfect place for such questions!
>>
>>As Chris says, you can use subinterfaces, which are supported by IXP 
>>Manager, at least certainly the type that creates what appears via 
>>snmp as a standard interface, like Arista’s implementation.  Sample 
>>config below, but it needs a specific tcam profile, which you’d be 
>>best to get from your Arista support team, as any other 
>>config/services you have defined would need to be considered.
>>
>>The other, less technical way, is to use fanout ports. This means you 
>>burn a port for the uplink and then two ports for each member 
>>delivered via that uplink. See the docs for this at 
>>https://docs.ixpmanager.org/latest/features/reseller/.
>>
>>  - Barry
>>
>>Sample Arista Config
>>
>>vlan 10
>>    name peeringlan
>>
>>interface Ethernet25
>>    description Reseller: Acme Ltd
>>    load-interval 30
>>    no switchport
>>    no lldp transmit
>>    no lldp receive
>>    no sflow enable
>>
>>interface Ethernet25.2001
>>    description Cust: Resold Customer 1 Ltd
>>    load-interval 30
>>    encapsulation dot1q vlan 2001
>>    vlan id 10
>>    mac access-group l2acl-ixp-resold-cust in
>>    service-policy type qos input pm-subinterface-1g
>>    shape rate 1000000
>>
>>interface Ethernet25.2002
>>    description Cust: Resold Customer 2 Ltd
>>    load-interval 30
>>    encapsulation dot1q vlan 2002
>>    vlan id 10
>>    ...
>>
>>
>>On 21/04/2026 14:37:23, "Christopher Rössler via ixpmanager" 
>><ixpmanager at inex.ie> wrote:
>>
>>>Hi,
>>>Have you thought about using a reseller uplink interface for the 
>>>"other IXP" and putting the actual customers into resold 
>>>subinterfaces?
>>>
>>>Kind regards,
>>>
>>>chris
>>>
>>>On Tue, Apr 21, 2026 at 3:04 PM Roland Christanell | Telmekom via 
>>>ixpmanager <ixpmanager at inex.ie> wrote:
>>>>Hello,
>>>>
>>>>
>>>>
>>>>I hope this is the right place to ask this question.
>>>>
>>>>I am using IXP Manager v7.1.0 and have 2 customers that are 
>>>>connected on one port, the reason is that this is some kind for 
>>>>“transport” from another IXP and therefore multiple customers can be 
>>>>connected on one port.
>>>>
>>>>Currently only one member has the actual port assigned and this 
>>>>leads to the problem, that for the second one I have traffic graph 
>>>>and the traffic off both is seen on the graph of the first member.
>>>>
>>>>
>>>>
>>>>Best regards,
>>>>
>>>>
>>>>
>>>>Roland Christanell
>>>>Network Engineer
>>>>
>>>>Rechteck.png
>>>>
>>>>
>>>>
>>>>_______________________________________________
>>>>INEX IXP Manager mailing list
>>>>ixpmanager at inex.ie
>>>>Unsubscribe or change options here: 
>>>>https://www.inex.ie/mailman/listinfo/ixpmanager
>>>
>>>
>>>--
>>>Christopher Rössler, Network Engineer
>>>christopher.roessler at bcix.de
>>>+49 30 2332195 37
>>>
>>>BCIX Management GmbH
>>>Albrechtstr. 110
>>>12103 Berlin
>>>Germany
>>>
>>>Geschäftsführer/Managing Directors: Jens Lietzmann, André Grüneberg
>>>Handelsregister: Amtsgericht Charlottenburg, HRB 143581 B
>>
>>
>>Kind regards,
>>Barry O'Donovan
>>INEX Operations
>>
>>https://www.inex.ie/support/
>>+353 1 531 3339
>>
>>
>>_______________________________________________
>>INEX IXP Manager mailing list
>>ixpmanager at inex.ie
>>Unsubscribe or change options here: 
>>https://www.inex.ie/mailman/listinfo/ixpmanager
>
>
>--
>Salvador Bertenbreiter
>(+51) 947 145 352
>(+57) 323 802 9009
>

Kind regards,
Barry O'Donovan
INEX Operations

https://www.inex.ie/support/
+353 1 531 3339

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