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Stefan Richter <stefanr@s5r6.in-berlin.de> says: | As far as I can tell, it would be best to ignore max_rec and sspd from ARP | and NDP but keep using the respective information from firewire-core | instead (handed over by fwnet_probe()). | | Why? As I noted earlier, RFC 2734:1999 and RFC 3146:2001 were apparently | written with a too simplistic notion of IEEE 1394 bus topology, resulting | in max_rec and sspd in ARP-1394 and NDP-1394 to be useless, IMO. | | Consider a bus like this: | | A ---- B ==== C | | A, B, C are all IP-over-1394 capable nodes. ---- is an S400 cable hop, | and ==== is an S800 cable hop. | | In case of unicasts or multicasts in which node A is involved as | transmitter or receiver, as well as in case of broadcasts, the speeds | S100, S200, S400 work and speed S400 is optimal. | | In case of anything else, IOW in case of unicasts or multicasts in which | only nodes B and C are involved, the speeds S100, S200, S400, S800 work | and speed S800 is optimal. | | Clearly, node A should indicate sspd = S400 in its ARP or NDP packets. | But which sspd should nodes B and C set there? Maybe they set S400, which | would work but would waste half of the available bandwidth in the second | case. Or maybe they set S800, which is OK in the second case but would | prohibit any communication with node A if blindly taken for correct. | | On the other hand, firewire-core *always* gives us the correct and optimum | peer-to-peer speed and asynchronous packet payload, no matter how simple | or complex the bus topology is and no matter in which temporal order nodes | join the bus and are discovered. CC: Stefan Richter <stefanr@s5r6.in-berlin.de> Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net> |
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| .. | ||
| core-card.c | ||
| core-cdev.c | ||
| core-device.c | ||
| core-iso.c | ||
| core-topology.c | ||
| core-transaction.c | ||
| core.h | ||
| init_ohci1394_dma.c | ||
| Kconfig | ||
| Makefile | ||
| net.c | ||
| nosy-user.h | ||
| nosy.c | ||
| nosy.h | ||
| ohci.c | ||
| ohci.h | ||
| sbp2.c | ||