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FTTC Modem: Difference between revisions
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[[Category:Routers]]
=No longer supplied=
Note, these Openreach modems are no longer supplied.
With FTTC, BT
▲With FTTC, BT will supply and install a VDSL modem (the Active NTE in BT speak), You will then need a PPPoE device (router or software) to use the service.
*PPPoE Service Name = Blank
*PPPoE username = as supplied,
*PPPoE password = as supplied
*MTU = 1500 (if your equipment can handle baby jumbo frames and [http://www.faqs.org/rfcs/rfc4638.html RFC 4638]), otherwise 1492
*Auth Protocol = CHAP
= FTTC Modem =
*Huawei EchoLife HG612
Openreach tend to install the FTTC modem to match the DSLAM in the Cabinet. However,
[[File:FTTCModems.png|600px]]
The 2 modems both look very similar! There are a few differences though:
*The ECI is larger
*The ECI has '
*The ECI has a yellow LAN1 socket, The Huawei has a metallic LAN1 socket
[[File:FTTCModem-LEDs.png|600px]]
The FTTC modem supplied by Openreach is described in detail on [http://www.btplc.com/sinet/SINs/pdf/498v7p1.pdf BT SIN 498]
=Router Throughput=
|Linksys WRTU54G-TM
|24Mb
|style="color:red"|~
|Running OpenWRT trunk from [http://wiki.scottn.us here]. Disconnected PPP due to link saturation at default settings - adjust PPP options for stability
|-
|16Mb
|style="color:green"|16Mb
|It should be able to handle around
|}
=FireBrick 2700=
The Firebrick 2700 is a great router for FTTC, and even bonding FTTC. See the [[:Category:FireBrick|Firebrick]] pages for more info
=Testing and using FTTC with just a computer=
=RFC 4638 Information=
When using a router with an external modem, one has to use PPPoE on the router as the connection method. This normally means that the MTU on the PPPoE link
Some pointers regarding RFC 4638, PPPoE and Linux-based routers.▼
can be no higher than 1492 octets (PPPoE has an 8 octet overhead, and the whole packets has to fit in a 1500 octet Ethernet frame). However, there is a
#The wan interface needs to be set to an MTU of 1508 on the assumption that there needs to be room for the 1500 mtu PPP package on the way to the modem (1500 may work - untested though).▼
technique to use ''baby jumbo frames'' to extend the Ethernet frame size to 1508 octets and allow the full 1500 octets on the PPPoE link.
In order to use baby jumbo frames on FTTC, the customer's router must support RFC 4638. It is not enough that the router supports baby jumbo frames via
configuration, the router must be able to do the negotiation described in RFC 4638.
▲#The wan interface needs to be set to an MTU of 1508 on the assumption that there needs to be room for the 1500
#You will require the unreleased ppp 2.4.6. In testing, ppp 2.4.5 with the rp-pppoe plugin updated to the latest version seems to work, although a recompile will be necessary. This can be fetched from ppp's website / git.
#Using ppp's debug option will allow you to see the rp-pppoe plugin negotiating a PPP-Max-Payload option
Ensure you're using [[Linux|kernel 2.6.34+ or 2.6.36.3+]]
=RFC 4638 OpenWRT 12.09 (Attitude Adjustment)=
Patches for WNDR3x00 are available at https://github.com/mattwillsh/openwrt-wndr3x00-rfc4638
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