TWiki> DICE Web>InfrastructureUnit>AHM2008 (revision 7)EditAttach

All Hands Meeting 2008 - Network Planning


The AHM2008 Meeting is scheduled to take place in Edinburgh, from the 8th - 11th September 2008: see We are responsible for the data networking.

1. General Requirements


AHM2008 takes place both in AT and in the Informatics Forum. Exhibitors will have booths in both the main concourse of AT, and in the large meeting room on the ground floor of the Forum - see the following layouts. All such booths need wired networking and power.


There will be 600 or so delegates attending. They all need access to the wireless network. As far as I am aware there is no expectation that delegates should have access to our wired network.

Getting things networked and powered in the Forum is our (ie Informatics) responsibility; provision in AT is also our responsibility but requires coordination with IS.

Wireless networking

Wireless networking needs to be arranged for all delegates, and for all exhibitors, in both venues.

Many delegates to AHM2008 might be able to access the wireless network via Eduroam - but we shouldn't assume that. The possibility of usind Eduroam should be offered as an option to delegates in their 'how to use the wireless network' notes.

Wired networking

Wired networking needs to be set up for the exhibitors' booths in both AT and in the Informatics Forum, as well as the registration area. There are 16 booths in AT and 12 in the Forum - see the layouts above.

From previous meetings, the expectation is that every stand will have something like 10 (or so) wired connections. (At AHM2007, the arrangement was that every stand had a single 100 Mbps uplink to the network and a 24-port switch.)

Some (but we don't know how many, and we may not know this until very late in the day) exhibitors might want externally visible static IP addresses for incoming connections, but most (?) should be satisfied with dynamic IP addresses, or internal addresses which hide behind NAT.

Actual bandwidth usage from previous AHM Meetings seems modest - graphs from 2005 show a peak of about 2.5 MB/s.


Question: what arrangements do we need to make for wired networking in the AHM2008 presentation venues? i.e. for presenters/presentations themselves? Is this our responsibility? (I think this should be handled jointly by 'Edinburgh First' and 'MALTS', and is not our concern - but is that correct?)


Power cabling needs to be installed to each exhibition booth and it's not sufficient to suggest using, for example, the existing floorpoints in the AT concourse area. The commercial organiser Bob Whiteley has said that:

The booths will have lighting as well as power requirements: the people installing the booths will also wire in the lighting and sockets, and this is usually done overhead so as to meet H&S requirements regarding trailing cables, although there will be some in the booths themselves. This is why I need to know where they can tap into some mains power so they can run a mains cable to a breaker at the end of the booths.

I don't think the details of power cabling are our responsibility, but it is likely that, in AT at least, we will need to route network cables via the same overhead arrangement used for the power cables.

2. What Nottingham did in 2007

From Phil Harrison, Network Team Leader, University of Nottingham Information Services:

Attached are the handouts we gave to exhibitors and delegates last year, plus a form for pre-recording MAC addresses (this is for info only, not essential). We used public IP address space that is permanently allocated to the conference centre here. We had 30 IP addresses provided for incoming connections requirements on a predefined rule on our default deny firewall.

Our exhibition hall has a grid of datapoints in the ceiling. In previous years we had put a small number of 48-port switches on to boards mounted on the top of the booth walls, with cables run down into groups of booths from each one. However, we found this was a bit of a nightmare to tidy up afterwards, when the stands were being dismantled at the same time, so last year we put a switch into each stand pretty much with one uplink from each switch to the ceiling.

I can't recall anyone having any difficulties with the DHCP or fixed IP arrangements, as defined on the handouts.

3. Initial ideas and suggestions

Wireless networking

  • This seems straightforward: we should just be able to use the existing University wireless infrastructure.

  • We need to ensure that there is adequate wireless coverage in the Forum.

  • We need to ask the meeting organizers to set up, via IS, as many wireless accounts as are necessary to cover all delegates and exhibitors - this may be 700 or so - and to distribute these usernames and passwords to delegates/exhibitors as they register on the first day. (We also need people to sign a usage agreement.) IS charge 1 per such account. We need a procedure in place to quickly arrange more accounts during the the running of the Meeting, should this prove necessary.

  • There should be no need for MAC address registration. (This has been done in the past - see AHM2007macaddresss.pdf- but I don't think applies to us.)

  • We need to warn IS to expect increased usage of the wireless network in the two venues for the duration of the meeting.

Wired networking

  • We need to define both the the physical and logical layout of the wired networking:

    • Physical: we need to specify how many uplinks of what speed are to be used; what switches and/or routers are to provided; and how cables are finally to be run to the exhibitors' stands in both venues.
    • Logical: we need to specify and configure the network to which each final cable is connected. (This might be as simple as just carrying a particular VLAN.)

  • It would seem useful - from the exhibitors' points of view - if the wired networking arrangements were identical in both AT and the Forum - but this isn't essential.

  • At a meeting on 11th June, Duncan Phillips of IS:

    • said that there would be no problem running 'sufficient' network cables from the columns in AT to the exhibitors' area;

    • made an initial suggestion of sharing one 48-way switch between each set of four booths (i.e. using four such switches in all), each such switch to be served by a single 100Mb/s uplink;

      [ Comment : This seems a high-contention arrangement which may not be suitable. I think my preference would be to provide a switch of some kind, with its own uplink, per booth. Whatever we do we have to be able to configure the individual ports on each switch appropriately. That is, we have to be able to satisfy the requirement that certain exhibitors might want one or more fixed IP addresses, for example, as well as other more usual dynamic IP connections. ]

    • suggested configuring all AT network ports thus supplied to use the University's LapLan2 service (

      The LapLan2 service gives a wired connection that uses the same authentication mechanism as used on the wireless service. The advantage is that an exhibitor/delegate who has a wireless account should be able to use the same account for wired access via LapLan2. Moreoever a LapLan2 connection provides an non-firewalled address which might (?) be suitable for exhibitors requiring incoming connections. (But note that the IP address is not fixed which might cause a problem. Does IS provide a Dynamic DNS service?)

      [ Question: in general, can a single user have more than one simultaneous LapLan2 connection? We need to cater for the situation where a single exhibitor wants access to more than one wired port: can he/she do this using a single LapLan2 account, or will he/she need multiple accounts? ]

  • We need to find out whether or not a LapLan2 connection is in fact suitable for incoming connections of the the type that exhibitors require. If not, we need a Plan B to provide up to 20 or so such connections in each of the two venues.

    If the LapLan2 idea does seem okay, then, for the Forum, we could arrange to carry the LapLan2 VLAN and provide exactly the same arrangement as in AT - so the use of LapLan2 has the advantage of providing a common service to both sites. (It has the disadvantage that it is outside of our control - but we have this problem for the AT site in any case.) If we don't want to use LapLan2 then we need to decide on alternative arrangements for both venues.

  • For the Forum, we need to confirm that network cables can be laid to all of the booth areas, and to the registration area.

  • I think we should forget about any ideas of NAT routers and internal addresses etc. (which have been suggested). Instead, let's think about providing one switch per booth (or booths), and then making sure we can configure those as we want.

    Questions :

    • Who will provide these switches (and all necessary cables etc.)?
    • If we do not use LapLan2 and we need to explicitly configure every port on every switch, how do we arrange this? (We can do this easily for Informatics switches - but what about those in AT?)

NOTE: Changes recently advertised to both the University wireless and LapLan2 networks - see Wireless Network Client IP Address Changes, Summer 2008 mean that both wireless and LapLan2 connections will be private addresses behind NAT routers by the time AHM2008 is running. So we definitely need an extra arrangement to provide for cases where the exhibitor wants a connection suitable for incoming connections.

One suggestion might be as follows:

  • Configure all exhibitors' booths in AT as LapLan2.
  • Carry the LapLan2 VLAN to the Forum, but, in addition, configure as many ports as are necessary there for incoming connections in some suitable way. (Question: how, exactly?)
  • Decree that exhibitors wanting connections suitable for incoming traffic must be located in the Forum.

Is this sensible/possible?

Another alternative might be to treat AT and the Forum as completely distinct cases; and issue guidelines specific to each.

AT Logical:

  • Use whatever logical network facilities IS can provide.
  • All switch ports to be configured as LapLan2, and all exhibitors to be given sufficient LapLan2 accounts. (Note: need to check whether or not a single LapLan2 account can be used for multiple simultaneous connections.) Advertise the fact that such connections are on the private 172.20 network; are okay (via NAT) for outgoing connectivity; are not okay for incoming connectivity.
  • Check with IS that incoming connectivity via public addresses is possible, and confirm what arrangements need to be made for this.
  • Assuming so: advise exhibitors that connections offering incoming connectivity are possible, and ask any exhibitors who may want incoming connectivity to contact us with their specific needs as far in advance as possible.

AT Physical:

  • Arrange 'several' 'n-way' (both to be defined) switches (each to have a 100Mb/s uplink), with each switch being shared between 'm' (ditto) booths.
  • IS to provide all switches.
  • Need cabling for power and uplink to each switch. Uplink leads to be routed from columns in AT. Power leads to be routed from where?
  • Switch<->booth connections provided by as many flying leads as are necessary. Leads to be provided by whom?
  • Advise conference organiser of this physical layout.

Forum Logical:

  • Use the Informatics network only; no other IS facilities/VLANs etc.
  • Set up a conference subnet, and configure all switch ports to offer DHCP connectivity on that subnet with no further authentication. Advertise the fact that all such connections offer outgoing connectivity, and can be set up for incoming connectivity if required. (Note: the firewall configurations necessary to do this have to be specified.)
  • Ask any exhibitors who may want incoming connectivity to contact us with their specific needs as far in advance as possible.

Forum Physical:

  • Arrange 'several' 'n-way' (both to be defined) switches (each to have a 1Gb/s uplink), with each switch being shared between 'm' (ditto) booths.
  • Us to provide all switches.
  • Need cabling for power and uplink to each switch. Uplink (and power?) leads to come from floorboxes in both rooms. Need to have these floorboxes sufficiently live (none are yet live): coordinate this with Dave Hanilton.
  • Switch<->booth connections provided by as many flying leads as are necessary. Leads to be provided by us, presumably. (How is this costed, and who can/should we charge?)
  • Advise conference organiser of this physical layout.

4. Final conclusions

Wireless networking

Exactly as above. Advertise the fact that such connections are on the private 172.20 network but are okay (via NAT) for outgoing connectivity.

Wired networking

The final plan is as follows:


  • Treat wired networking AT and the Forum in exactly the same way. This gives a consistent interface to the exhibitors, and doesn't increase our work since we have to do all the set-up in the Forum anyway.
  • Use a single Informatics VLAN to deal with all wired networking. Arrange for this VLAN to be carried by IS on the relevant ports in AT. (gdmr advises that this is no problem: we just need to request it. Alan Boyd - a.boyd@ed - should be the appropriate contact.)
  • Set up an Informatics /23 subnet to run on this VLAN. (Subnets 110 and 111 will shortly be free for reuse in this way.) A /23 subnet This gives 510 addresses, which is enough. (There are 28 booths, and we will offer each one a 16-port mini switch, giving 448 possible connections in total.)
  • Set up DHCP service on this subnet with the possibility of allocating fixed addresses for any exhibitor who requests this. (gmdr says that solti and boulez should be available by the required time and that either or both can be used as inf servers for this purpose.)
  • Advise exhibitors that static IP addresses are possible and that these can be given firewall exemptions, but that all such requests need to be made in advance. (For a firewall exemption, we need a static address; for a static address, we need their MAC address.)


  • Install a 16-port desktop mini-switch (eg Netgear FS116: in each booth. This requires a single power socket, and single Cat-5 cable running back to a central switch. Such cabling should be able to be routed in the same way as the power cabling where this suits our purpose. (Use of such switches means that everything has to be running on a single VLAN - but this is what we propose to do anyway.)
  • The single uplink from each mini-switch should be routed direct to the IS switch in AT; in the Forum, it may go to a floorbox. All to be decided.

General questions

  • Who supplies the switches, cables, etc.? Who pays for what's needed? Netgear FS116 mini-switches cost about 50 each: we need 28, making a total of 1400. We also need to allocate cables. Is there a budget for all of this?
  • How can we ensure that whatever physical arrangement we suggest can be tidily installed in the booths? How do we route the necessary network cabling for the switches?
  • Network information for delegates/exhibitors:
    • What's the name of the SMTP host on the IS network? Is the appropriate one?
    • What are the wireless SSID's?

5. Things to be done

  1. Fairly urgent, ideally to be done by Friday 27.6.08 : I need to issue guidelines to exhibitors (via the meeting organiser) that explain the networking set-up they can expect, so we need to quickly firm this up. (See last year's example of this: AHM2007exhibitors.pdf)

  2. Likewise, I need to issue guidelines to delegates explaining network usage. This should mainly cover wireless usage - but may (?) also cover use of the University's LapLan2 service ( if (and only if) this applies to network ports which are accessible to the delegates. (A 'wireless' account seamlessly give access to LapLan2, and vice versa, as far as I understand it.)

    Question: Will any such ports actually be available to the delegates? And will delegates expect to be able to use the wired network? I would think not, but ...

    (Last year's example of the 'guidance to delegates': AHM2007delegates.pdf)

  3. ...

6. Related Information

  1. Computing Services - IT Facilities for Conferences (Summary)
  2. Computing Services - IT Facilities for Conferences at Edinburgh University
  3. DICE - Computing Facilities for Conferences
  4. The University Wireless Network Service - and NB Wireless Network Client IP address changes, Summer 2008
  5. Basic Introduction to the LapLAN2 Service on EdLAN

-- IanDurkacz - 20 Jun 2008

Edit | Attach | Print version | History: r10 < r9 < r8 < r7 < r6 | Backlinks | Raw View | Raw edit | More topic actions...
Topic revision: r7 - 27 Jun 2008 - 15:42:12 - IanDurkacz
This site is powered by the TWiki collaboration platformCopyright © by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding TWiki? Send feedback
This Wiki uses Cookies