Oh hai

I’ve spent a bit of time over the last few days switching everything at home from Cablecom to Swisscom as soon as I found out that FTTH was possible in my apartment.

I wanted to continue using my existing router (Cisco 1921), especially because the Centro Grande didn’t really want to go into bridge mode. As is well known, there are a few things you have to consider before the whole thing runs over FTTH and SCTV also works.

This blog entry was a big help: [http://phaq.phunsites.net/2012/04/09/swisscom-vivo-ftth-Anschluss-mit-cisco-router-betreib/](http://phaq.phunsites. net/2012/04/09/swisscom-vivo-ftth-connection-operate-with-cisco-router/)

However, it does not describe how to properly set up the network for SCTV. So I’m documenting my experiences here so that someone might save time if he or she wants to recreate this.

Parts list:

A list of all components used

• Cisco 1921 ISR G2 incl. 4-port Gigabit switch
• Media converter SFP<->RJ45, 100 Mbit/s
• SFP (TX/RX=1310/1550nm, SM, DDM, 15 dB, 20km, LC/PC connector)
• Glass patch cable LC/APC to LC/PC, single mode, 3m, simplex

The glass cable that comes with the FFTH offering has an F-3000 connector. These are relatively new and not available everywhere. However, a more readily available cable with an LC connector is compatible with the hole in the FTTH socket. So the decision was easy.

More interesting was the right choice of the optical transciever (SFP) and the right media converter to convert the light signals into electrical signals.

Swisscom apparently sends light at 1550nm and receives it at 1310nm. This enables the use of a single fiber per Anschluss, as fiber pairs (i.e. two fibers) are not required per Anschluss. So if Swisscom sends on 1550nm, my interface has to receive on 1550nm. These interfaces must therefore always be used in pairs. I just guessed and got lucky. Otherwise I would have had to return the SFP and buy the other one 😉

This SFP then goes into the media converter, which I connect to the router with a “normal” Cat5 network cable. In this scenario, the bridge is not the Centro Grande or a modem, but the media converter (seen in the picture).

By the way, the thing is cool because it automatically passes on the status of the ports. So if the glass port is down (e.g. no light or an excavator tears the glass cable out of the street), the RJ45-Anschluss is also down. So the media converter is more or less transparent to the devices in between.

So. And now to configure the WAN interface:

interface GigabitEthernet0/1.10
description Swisscom FTTH WAN
encapsulation dot1Q 10
ip dhcp client client-id GigabitEthernet0/1
ip dhcp client class-id 100008,0001,Cisco,e02f.6dxx.xxxx,15.3(1)T,FCZXXXXXXXX
ip dhcp client hostname own-hoempf-endpoint
ip address dhcp
no IP redirects
no ip unreachables
no ip proxy arp
ip nat outside
ip virtual reassembly in
no cdp enable
end

The one with the DHCP client ID etc. comes from the linked blog-article above and worked straight away. Thank you at this point to Gianpaolo 😉

In short, Swisscom tags everything in VLAN10 for FTTH, including Swisscom TV. I think Swisscom calls this “All-IP”.

I won’t go into the further configuration specifically. If anyone wants to know more, there is enough space below 😉

Multicast now needs to be configured for Swisscom TV, that’s the interesting part. Swisscom uses the IP 1.1.1.1 as the rendez-vous point (actually not ok, because the IP is not private and not assigned to Swisscom, but that is a different topic).

ip pim rp-address 1.1.1.1

The interfaces also have to be defined for the PIM sparse mode (I got some of the configuration from [here](https://community.swisscom.ch/t5/Discussions-sur-l-internet-de/Configuration-Cisco- 887VA/td-p/80001)). The WAN interface then looks like this:

interface GigabitEthernet0/1.10
description Swisscom FTTH WAN
encapsulation dot1Q 10
ip dhcp client client-id GigabitEthernet0/1
ip dhcp client class-id 100008,0001,Cisco,e02f.6dxx.xxxx,15.3(1)T,FCZXXXXXXXX
ip dhcp client hostname own-hoempf-endpoint
ip address dhcp
no IP redirects
no ip unreachables
no ip proxy arp
ip pim sparse mode
ip nat outside
ip virtual reassembly in
ip igmp query-max-response-time 8
ip igmp version 3
ip igmp query interval 10
ip igmp querier timeout 60
no cdp enable
end

The internal interface:

interface Vlan1
ip address 192.168.10.1 255.255.255.0
ip pim sparse mode
ip nat inside
ip virtual reassembly in
ip igmp helper-address 1.1.1.1
ip igmp query-max-response-time 8
ip igmp version 3
ip igmp explicit tracking
ip igmp query interval 10
ip igmp querier timeout 60
end

So far everything is working perfectly. I haven’t refined the QoS configuration yet, but a general config (DSCP based fair queuing) seems to work without any problems so far. You don’t have to (and can’t) “shape” the incoming traffic, etc. Swisscom does that:

policy map QoS
class class default
fair queue
random detect dscp based

interface GigabitEthernet0/1
description Swisscom FTTH
no ip address
duplex car
speed auto
no cdp enable
service policy output QoS

If anyone wants to do this and still has questions or encounters problems, I would be happy to help here.

But very important:

This whole story is almost certainly not supported by Swisscom at all, so if something goes wrong, Swisscom won’t be able to help until the Centro Grande gets involved again. Anyone who follows the above does so at their own risk!

I hope this all helps someone who enjoys configuring this themselves 🙂 Cheers!

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