On 22/03/15 03:03, thufir wrote:> On Fri, 13 Mar 2015 20:33:13 -0500, Brian Franklin wrote: > >> If your phones support PoE, >> >> I have had huge success with Zyxel: >> http://www.amazon.com/ZyXEL-ES1100-16P-16-Port-Ethernet-Unmanaged/dp/B00 >> 5GRETMM/ref=sr_1_3?ie=UTF8&qid=1426296572&sr=8-3&keywords=zyxel+poe >> >> If you want to go even cheaper, I have successfully used these as well: >> http://www.amazon.com/TRENDnet-8-Port-100Mbps-Switch-TPE-S44/dp/B000QYEN >> 1W/ref=sr_1_10?ie=UTF8&qid=1426296706&sr=8-10&keywords=poe+8-port >> >> >> Brian Franklin NTG, Inc. - "Problem Solved" > > > This is the router/modem gateway the ISP supplied: > > http://www.cisco.com/web/consumer/support/modem_DPC3825.html > > When I connect one of these switches to the router, that doesn't create a > double-NAT problem? >No, ethernet switch works at lower / physical / MAC layer, NAT is 'above' that; so as long as everything is OK with your TCP/IP settings everywhere, a switch is entirely transparent to TCP/IP (or generally, when it's encapsulated into MAC traffic). All that happens at a level totally transparent to the TCP/IP stack In a way, an Ethernet Switch is /the/ network near you, your cables are 'just' interconnects. HTH, el es> > thanks, > > Thufir > >
On Mon, 23 Mar 2015 10:11:54 +0000, Lukasz Sokol wrote:> No, ethernet switch works at lower / physical / MAC layer, NAT is > 'above' > that; > so as long as everything is OK with your TCP/IP settings everywhere, > a switch is entirely transparent to TCP/IP (or generally, when it's > encapsulated into MAC traffic).so how does a client pc find the server if there's no NAT? by IP address?? That makes no sense, to me, if the switch isn't assigning addresses. -Thufir
> so how does a client pc find the server if there's no NAT? by IP > address?? That makes no sense, to me, if the switch isn't assigning > addresses.Switches have a MAC table that keeps track of which MAC addresses are on which ports. That's how they decide where to route packets. http://en.wikipedia.org/wiki/CAM_Table http://en.wikipedia.org/wiki/OSI_model -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.digium.com/pipermail/asterisk-users/attachments/20150323/284262b1/attachment.html>
On Mon, 23 Mar 2015, thufir wrote:> so how does a client pc find the server if there's no NAT? by IP > address?? That makes no sense, to me, if the switch isn't assigning > addresses.The 'endpoint' (pc, softphone, mobile, desk set, etc.) 'finds' the server's IP address when: ) You configure the endpoint with the IP address or host name of the server. This happens either by a web page you fill out on the endpoint or a configuration file that is downloaded by TFTP, FTP, HTTP, etc. ) You configure SRV records in your DNS. I think the old IAXy did some sort of discovery on port 9999, but I don't remember if it was device or server discovery. -- Thanks in advance, ------------------------------------------------------------------------- Steve Edwards sedwards at sedwards.com Voice: +1-760-468-3867 PST Newline Fax: +1-760-731-3000
On 23/03/15 16:37, thufir wrote:> On Mon, 23 Mar 2015 10:11:54 +0000, Lukasz Sokol wrote: > >> No, ethernet switch works at lower / physical / MAC layer, NAT is >> 'above' >> that; >> so as long as everything is OK with your TCP/IP settings everywhere, >> a switch is entirely transparent to TCP/IP (or generally, when it's >> encapsulated into MAC traffic). > > > so how does a client pc find the server if there's no NAT? by IP > address?? That makes no sense, to me, if the switch isn't assigning > addresses. > > > -Thufir > >+1 to what Kevin said, and there is a protocol running on pretty much every ethernet based network, named ARP : Address Resolution Protocol, by which ALL the clients learn ALL the surrounding clients (including the one that is the GATEWAY) MAC/IP combinations. Simplified, the encapsulation of ethernet packets is sort-of | MAC Header | IP Header | Packet |[MAC Source address][MAC Destination Address]|[Source IP][Destination IP]|[The rest of packet] [order and number of fields not necessarily real-life, for illustration purposes only] now the MAC source/dest fields are added AND REMOVED as needed when the packet passes from card to computer/router, then from computer/router to card; as the MAC fields don't make sense in wider area networks; 'dumb' switches don't participate/snoop in ARP, only store a table of what card MAC address they encountered on source MAC field of packets coming from that interconnect manageable switches /can/ participate and filter in the ARP process if told so and have such option. HTH, el es