Rtp Frame Size; Tftp Block Size - Mitel MiVoice Manual

DMZ Deployment Profile
When the MBG server is deployed in a DMZ (see Figure 3 on page 5), all endpoints should send RTP to the IP
address seen by the Mitel AMC during a sync operation. This is the MBG server's publicly-visible address after
any NAT by the DMZ firewall. This address is configured automatically when DMZ mode is selected.
If this address is incorrect for some reason (such as multiple layers of NAT), use the Custom profile to enter the
correct address.
Gateway Deployment Profile
A standard example of the gateway deployment is shown in Figure 2 on page 4. In this configuration, the WAN
interface on the server is routable on the "public" network. This is referred to as the "set-side" streaming address,
to which teleworker devices and service provider trunk equipment sends RTP. The "public" network is typically
the Internet, but may instead be a managed service-provider network, MPLS LAN extension, corporate network,
etc.
The LAN interface is attached to the private network. This is referred to as the "ICP-side" streaming address, to
which LAN devices (phones), conference bridges, ICPs, voicemails, etc send RTP. The private and public
addresses must be on different IP networks.
The defaults are usually acceptable. However, if not, they can be changed by using the Custom profile.

12.4 RTP Frame Size

By default, the RTP frame size is auto-negotiated between the endpoints. A size of 20 ms is common in North
America, with 40 ms becoming common in Europe. If needed, the administrator can force use of a particular
frame size. For example, some SIP trunk service providers insist on a particular RTP frame size.
The Configuration tab holds the global master setting. This setting is used as the default, and should be left on
"Automatic" unless there is a pressing need to change it. Overrides can be placed on specific devices and trunks
as required. For example, certain wireless networks handle RTP streams using larger (e.g. 40 ms) packets better
than streams using smaller ones.
Note: The frame size override only affects the streams to and from devices. The ICP-side streaming is always
auto-negotiated. On SIP trunks, both WAN and ICP sides can be specified separately.

12.5 TFTP Block Size

MiNet devices use the TFTP protocol to fetch their firmware from the MBG server. The Mitel TFTP server is
slightly non-standard – it uses symmetric UDP to traverse NAT devices, and a "sliding window" to improve
performance – but is otherwise RFC-compliant.
The default block size in the TFTP protocol is 512 bytes, and with large firmware loads in a lock-step protocol
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like TFTP this can take a prohibitively long amount of time to download. MBG employs the TFTP "blksize"
option to attempt to transfer 4096 byte blocks, if possible. Depending on one's network this may or may not be
possible: the large packets will require fragmentation on a standard Ethernet network with a 1500 byte MTU,
and some ISPs do not permit this.
Set the global TFTP block size to the largest value that works. If your MiNet devices are experiencing issues
downloading firmware or HTML applications, change the value to 1024 bytes.
Only the options in the pulldown (512, 1024, 2048 or 4096) are permitted.
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Receipt of each block must be acknowledged before the next block is sent
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