Inalp Networks SmartWare Release 2.10, Software Configuration Manual, Page: 206 / 357

206 PPP Configuration
Software Configuration Guide Release 2.10, Revision 1.00
SN(cfg)# context ip router
SN(ctx-ip)[router]# interface ppp_interface
Step 3 node (if-ip)[ name ]#ipaddress
unnumbered
or
node (if-ip)[ name ]#ipaddress
dhcp
or
node (if-ip)[ name ]# ipaddress
ip-address netmask
The PPP remote peer offers an IP address for the
IP interface. The IP interface adopts this IP
address.
Once PPP has established an IP connection, the IP
interface can use DHCP to acquire an IP address.
It sends a DHCP Discover message (which is an
IP broadcast) to the IP network to which PPP has
established connection. If no DHCP Server is
present, the IP interface does not adopt the IP
address offered by the PPP remote peer but leaves
the IP address undefined.
The IP interface requests from the PPP remote
peer to use the IP address
ip-address . PPP
repeatedly tries to set-up a connection until the
remote peer accepts this IP address. It does not
accept any other IP address offered by the PPP
remote peer. The parameter
netmask specifies the
size of the subnet in case ‘no point-to-point’ is
configured.
Step 4
(optional)
node (if-ip)[ name ]#no tcp
adjust-mss { rx|tx }
{ mtu | mss }
Limits to the MSS (Maximum Segment Size) in
TCP SYN packets to
mss or to MTU (Maximum
Transmit Unit) - 40 Bytes, if ‘ mtu ’ is used. ‘ rx ’
applies to packets which arrive inbound at this IP
interface, ‘
tx ’ to packets which leave outbound of
this IP interface.
PPP over Ethernet connections impose an
overhead of 8 Bytes (PPP: 2 Bytes, PPPoE: 6
Bytes). Some Ethernets do not allow payloads
larger than the 1500 Bytes which the standard
defines. IP packets must therefore not contain
more than 1492 Bytes when transmitted over such
connections. Reducing the MTU / MRU to 1492
Bytes does not always solve the problem because
many sources do not allow fragmentation of the
IP packets they send (they set the ‘Don’t
fragment’). However, these sources limit the size
of the IP packets according to the MSS which their
peers announce in the TCP SYN packets.
It is recommended to use ‘
mtu ’ inbound and
outbound.
Step 5
(optional)
node (if-ip)[ name ]#use profile
napt name
Assigns the NAPT profile name to applied to this
IP interface. See Section ??? to learn how to create
a NAPT profile.
Example: Create an IP Interface for PPP
The procedure below creates an IP interface which can be used for all three types of link layers. The
command lines ‘tcp adjust-mss’ only apply to Ethernet link layers.