BXOS 4.1 R2 Software Release Notes
2
Release 4.1 R2 Features
Forwarding
Static or dynamic Ethernet pseudowire—Dynamic Ethernet pseudowire over
an MPLS or GRE tunnel is supported. Static Ethernet pseudowire over a static
MPLS tunnel is supported. An Ethernet pseudowire positioned between two
provider edges (PEs) carries the Ethernet frames or 802.3 protocol data units
(PDUs) from one PE to another over an MPLS network. The Ethernet
pseudowire operates in one of the three modes: raw mode, tagged mode, or
tagged-default mode.
If an Ethernet pseudowire is operating in a raw mode, the
service-delimiting tags are never sent over the pseudowire. If a
service-delimiting tag is present when the frame is received from the
attachment circuit by the provider edge (PE), it is stripped (by the NSP)
from the frame before the frame is sent to the pseudowire.
If an Ethernet pseudowire is operating in tagged mode, every frame sent
over the pseudowire must have a service-delimiting VLAN tag. If the frame
as received by the PE from the attachment circuit does not have a
service-delimiting VLAN tag, the PE must prepend the frame with a
dummy VLAN tag before sending the frame on the pseudowire. This is the
default operating mode.
For more information about the Ethernet pseudowire, see the
BXOS Configuration
Guide
.
Increase in MTU size for Ethernet port interface (Routing mode)—The MTU is
configured for this interface by the user. In BXOS Release 4.1, the MTU value is
now limited to a maximum of 1900 bytes.
Increase in MTU size for Ethernet port interface (Attachment Circuit (AC)
mode)— In BXOS Release 4.1, the user can configure the MTU value for this AC
port and the AC port will not receive or transmit more than the configured MTU
value. This MTU value is now limited to a maximum of 1800 bytes per Ethernet
frame.
Increase in MTU size for Ethernet pseudowire—In BXOS Release 4.1, the MTU
value is increased to a maximum of 1800 bytes.
Increase in number of concatenation of cells for ATM pseudowire— In BXOS
Release 4.1, the number of concatenation cells is increased from 28 to 34 cells
to utilize the available increased payload size with an increase in the
network-facing Ethernet interface MTU.
Increase in MTU size for GRE tunnel interfaces— In BXOS Release 4.1, the
maximum MTU value is increased from 1500 bytes and is limited to 1900
bytes.
For more information about the change in MTU size, see the
BXOS Configuration
Guide
.
Timing and
Synchronization
The BX7000 Multi-Access Gateway contains an advanced clocking module with
an internal oscillator that generates the clock signals that the BXOS software
uses. This clock provides Stratum 3 level accuracy and synchronizes the
time-division multiplexing (TDM) and Ethernet interfaces with various available
reference clocks.
