HI Sri, On Mon, Feb 5, 2018 at 10:25 PM, Sri Gundavelli (sgundave) < sgund...@cisco.com> wrote:
> Tom: > > Thanks! That sounds like some interesting trick. But, let me make sure I > understood this correctly. So, the > identifier space for the MN is encoded in the upper 64-bits. Now, the UE > can use those bits to generate any Identifier from that space, and use it > with the SIR prefix to form the 128 bit address. Bear with me, let me use > an example > > MN1 is assigned a prefix *2001:ABCD:CAFÉ*: / 48 > MN2 is assigned a prefix *2001:ABCD:FOOD*: /48 > > The SIR Prefix for that ILA domain is 2001:DB8::/64 > > So, the SIR Addresses can be formed using the 16-bit identifier space > left from the /48 prefix assignment? UE can form any identifier from bit > space? > > No, we want allow a full /64 assignment since that is being already deployed. > I can’t figure out the scheme from this below text in 6.3.2. I think I am > missing the context here. May be you guys discussed this before. > > ---- > > To support /64 prefix assignment with ILA, the ILA identifier can be > encoded in the the upper sixty-four bits of an address and the lower > > sixty-four bits are ignored by ILA. Since only a subset of bits are > available, a level of indirection can be used so that ILA transforms > the upper sixty four bits to contain both a locator and an index into > a locator (ILA-N) specific table. The entry in the table provides the > original sixty-four bit prefix so that ILA to SIR address > transformation can be done. > > ----- > > The SIR prefix and identifier are encoded in the upper 64 bits. Assuming the network has a /24, and address for /64 assignment might have this format. Network SIR/identifier IID 24 bits 40 bits 64 bits ------------------------|------------------------------|--------------------------------------------------| The IID part is arbitrarily assigned by the device, so that is ignored by ILA. All routing, lookups, and transformations (excepting checksum neutral mapping) are based in upper sixty-four bits. For SIR->ILA transformation, a lookup is done on the upper sixty four bits. That returns a locator that would have format something like: Network Locator Locator_index 24 bits 20 bits 20 bits ------------------------|-----------------------|--------------------------| The packet is forwarded and routed to the ILA addressed by locator (/44 route). ILA, the locator index is used as a key to an ILA-N specific table that returns the 40 bit SIR/identifier. This value is then written in the packet do ILA->SIR transformation thereby restoring the original address. The locator index is not globally unique, it is specific to each ILA-N. When a node attaches to an ILA-N, an index is chosen so that the table is populated at the ILA-N and the ILA mapping includes the locator and index. When a node detaches from on ILA, it's entry in the table is removed and the index can be reused after a holddown period to purge stale mappings. Tom > From: Tom Herbert <t...@quantonium.net> > Date: Monday, February 5, 2018 at 9:13 PM > To: Sri Gundavelli <sgund...@cisco.com> > Cc: Lorenzo Colitti <lore...@google.com>, "i...@ietf.org" <i...@ietf.org>, > dmm <dmm@ietf.org> > Subject: Re: [DMM] Fwd: New Version Notification for > draft-herbert-ila-mobile-00.txt > > > > On Mon, Feb 5, 2018 at 9:07 PM, Sri Gundavelli (sgundave) < > sgund...@cisco.com> wrote: > >> > best practice is not to use singleton addresses, but always to provide >> a /64 prefix. >> >> But, how does that work with ILA's approach of identifier management? >> With the previously IETF recommended approaches in RFC5213 and even in 3GPP >> architecture, per RFC3315, the network assigned a set of unique prefixes >> for each MN, allowed the MN to generate the identifiers. Even CGA >> addressing worked with the per-MN prefix model. >> >> But, with ILA there is no concept of prefix assignment. Will ILA network >> now generate a identifier block for each MN? Is DHCPv6 the only approach? >> >> Sri, see section 6.3.2. That describes encoding the identifier in the > upper sixty-four bits and using an indirection table to accommodate network > prefixes. > > Tom > > If that block is not summarizable, will it not result in mapping table >> size getting multiple many times? >> >> >> Sri >> >> >> >> >> >> From: dmm <dmm-boun...@ietf.org> on behalf of Lorenzo Colitti < >> lore...@google.com> >> Date: Monday, February 5, 2018 at 8:52 PM >> To: Tom Herbert <t...@quantonium.net> >> Cc: "i...@ietf.org" <i...@ietf.org>, dmm <dmm@ietf.org> >> Subject: Re: [DMM] Fwd: New Version Notification for >> draft-herbert-ila-mobile-00.txt >> >> On Fri, Feb 2, 2018 at 6:27 AM, Tom Herbert <t...@quantonium.net> wrote: >> >>> We like like to request that the dmm WG consider ILA as a candidate >>> protocol for the 3GPP "Study on User Plane Protocol in 5GC". >>> >> >> Echoing Tom's earlier comment about this: I think the address assignment >> sections (6.3 and 8.3) should be reworded to clarify that for general >> purpose hosts, best practice is not to use singleton addresses, but always >> to provide a /64 prefix. >> > >
_______________________________________________ dmm mailing list dmm@ietf.org https://www.ietf.org/mailman/listinfo/dmm