Hi Tero/ Yoav,

Thanks for your great comments. We are discussing this internally and will
get back to you in a few days.

Thanks,
Vishwas

On Mon, Sep 10, 2012 at 5:25 AM, Tero Kivinen <[email protected]> wrote:

> Paul Hoffman writes:
> > This appeared on the list over two weeks ago and it has received no
> > comments since. This is supposed to be the WG's main work item,
> > folks.
>
> My comments:
>
> > 2.2.  Gateway-to-Gateway AD VPN Use Case
> ...
> >    The spoke gateways can themselves come up and down, getting different
> >    IP addresses in the process, making th static configuration
>                                          ^^
> Typo.
>
> > 3.2.  Star Topology
> ...
> >    This solution however does not work when the spokes get dynamic IP
> >    address which the "hub gateways" cannot be configured with.
>
> I think star topology works fine with dynamic IP addresses. You just
> need to make sure that the spokes are the entities which brings up the
> link, i.e. immediately when they boot up they put up the IPsec link
> and keep it up all the time. There is other identities in the IPsec
> world than IP-addresses...
>
> I would remove the whole sentence.
>
> >    bandwidth.  A single packet in the hub-and-spoke scenario can be
> >    encrypted and decrypted three times.  It would be much preferable if
>
> In the pure hub-and-spoke model I cannot really see more than two
> times, one from the spoke to hub, and second time from the hub to
> another spoke. If there is hub to hub links also then it is not pure
> hub-and-spoke scenario anymore. I would replace the "three" with
> "multiple". I myself really had to read the first paragraph of this
> section again to notice that you talk there that this section says
> there can be multiple gateways selected as hub gateways.
>
> > 4.1.  Gateway and Endpoint Requirements
> ...
> >    2.  Gateways and endpoints MUST allow IPsec Tunnels to be setup
> >    without any configuration changes, even when peer addresses get
> >    updated every time the device comes up.
>
> This is unclear for me. Does that mean that anybody can connect to the
> gateway and the gateway MUST allow IPsec Tunnels to be setup without
> any configuration changes (like adding authentication credentials?). I
> do not think so.
>
> I think this needs to be clarified. Also endpoints do require
> configuration changes before they can first time connect to the AD
> VPN, for example you need to insert the credentials and most likely
> also point at least one gateway for them to fetch rest of
> configuration from them.
>
> If this is just trying to say that already configured devices in the
> AD VPN MUST be able to connect to any other configured device in the
> AD VPN at any time, even when the IP addresses are not known
> beforehand, then I think it should be said differently.
>
> Anyways I am not sure what this is trying to say.
>
> >    This implies that SPD
> >    entries or other configuration based on peer IP address will need to
> >    be automatically updated, avoided, or handled in some manner to avoid
> >    a need to manually update policy whenever an address changes.
>
> This is much more clear, and I think this most likely means that the
> first paragraph was trying to say that already existing AD VPN members
> should be able to connect other AD VPN members even when their
> IP-addresses are not static.
>
> Next question is how does the one member know to which address connect
> to if also the destination member has changing IP address? And how to
> punch holes to NATs that might be between them.
>
> >    3.  Gateways MUST allow tunnel binding, such that applications like
> >    Routing using the tunnels can work seamlessly without any updates to
> >    the higher level application configuration i.e.  OSPF configuration.
>
> I have no idea what this requirement means. What is "tunnel binding"?
> Where does this requirement come? Which use case drives this?
>
> >    4.  In a hub-and-spoke topology, spoke gateways and endpoints MUST
> >    allow for direct communication with other spoke gateways and
> >    endpoints.
>
> Hmm... why are you listing here spokes and endpoints as separate
> entries. In the terminology I understood spoke also includes
> endpoints?
>
> >    5.  One spoke MUST NOT be able to impersonate another spoke.
>
> If spoke does not imply endpoints, then we should say that this also
> applies to the endpoints, i.e. One endpoint or spoke MUST NOT be able
> to impersonate another spokes or endpoints.
>
> What about hubs? Are they allowed to impersonate other hubs? I assume
> yes, but then next question comes are hubs allowed to impersonate as a
> spoke or endpoint? Is there any requirement that when endpoint makes
> direct connection to other endpoint it knows that there cannot be any
> other parties listening on the link? If there is such requirement then
> also the hubs are not allowed to impersonate endpoints, but on the
> other hand if we use CA infrastructure, then the CA can always issue
> certificate allowing this kind of impersonation.
>
> >    6.  Gateways SHOULD allow for easy handoff of sessions in case
> >    endpoints are roaming, even if they cross policy boundaries.  This
> >    means that TCP session breakage and packet loss should be avoided,
> >    when possible.
> >
> >    This requirement is driven by use case 2.1.  Today's endpoints are
> >    mobile and transition often between different networks (from 4G to
> >    WiFi and among various WiFi networks).
>
> This cannot come from case 2.1, as that is endpoint to endpoint, so
> there is no gateway at all there. I would expect this would come from
> 2.3 i.e. the endpoint to gateway use case.
>
> Or does this mean gateways should allow handoff from the
> endpoint-gateway-endpoint to direct endpoint-endpoint link without
> breaking TCP sessions?
>
> >    8.  Gateways and endpoints MUST be able to work when they are behind
> >    NAT boxes.  However, it is especially difficult to handle cases where
> >    gateways are behind NATs and where two endpoints are both behind
> >    separate NATs.  In those cases, workarounds MAY be used such as port
> >    forwarding by the NAT or detecting when two spokes are behind
> >    uncooperative NATs and using a hub in that case.
> >
> >    This requirement is driven by use cases 2.1 and 2.2.  Endpoints are
> >    often behind NATs and gateways sometimes are.  IPsec should continue
> >    to work seamlessly regardless, using AD VPN techniques whenever
> >    possible and providing graceful fallback to hub and spoke techniques
> >    as needed.
>
> Does this also include discovery of the addresses? How about if we
> have two endpoints talking to each other and one of the nat boxes is
> restarted and one peers IP-address changes, and as the NATs are
> restricted nats, which means they cannot connect to each other at all
> after that without the help of the 3rd party. Also the 3rd party
> cannot connect to either one of them, thus the recover must then start
> from the endpoints so both of them connect to this 3rd party (hub) to
> recover from the situation.
>
> >    9.  Changes such as establishing a new IPsec SA SHOULD be reportable
> >    and manageable.  However, creating a MIB or other management
> >    technique is not within scope for this effort.
> >
> >    This requirement is driven by manageability concerns for all the use
> >    cases, especially use case 2.2.  As IPsec networks become more
> >    dynamic, management tools become more essential.
>
> I would rule configuration MIB out of the scope, but I would actually
> think it would be good idea to make reporting and statistics MIB. We
> really need one in the IPsec, and this is effort I think we should
> take here in ipsecme also for normal IPsec devices.
>
> I am sure we are still missing some requirements, but thats my
> comments for the existing requirements. I need to think bit more what
> other requirements we might have.
> --
> [email protected]
> _______________________________________________
> IPsec mailing list
> [email protected]
> https://www.ietf.org/mailman/listinfo/ipsec
>
_______________________________________________
IPsec mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/ipsec

Reply via email to